diff --git a/packages/react/src/Timeline/Timeline.issues.features.stories.tsx b/packages/react/src/Timeline/Timeline.issues.features.stories.tsx
index 20324b0b6ff..b31889bfb77 100644
--- a/packages/react/src/Timeline/Timeline.issues.features.stories.tsx
+++ b/packages/react/src/Timeline/Timeline.issues.features.stories.tsx
@@ -40,6 +40,8 @@ import Octicon from '../Octicon'
 import Token from '../Token'
 import classes from './Timeline.issues.features.stories.module.css'
 import {BoldLink, Examples, MutedTime, UserActor, VariantSection} from './internal/timelineStoryHelpers'
+import {actorTypeForLogin, ISSUE_TAXONOMY, toEventDataAttributes} from './taxonomy'
+import type {IssueEventType} from './taxonomy'
 
 /**
  * Issue Timeline event examples (Phase 2 of github/primer#6663).
@@ -104,6 +106,23 @@ export default {
   ],
 } as Meta<ComponentProps<typeof Timeline>>
 
+/**
+ * Serialize the taxonomy `data-*` contract (github/primer#6664) for one Issues
+ * event row. `type` is an ISSUE_TAXONOMY leaf; `category` + `visibility` are read
+ * from the catalog, so metadata leaves (labels, assignees, milestones, project
+ * fields, issue types, rename) pick up `visibility: 'auditOnly'` automatically.
+ * Pass the row's rendered actor login so `data-actor-type` resolves (every Issues
+ * event carries an actor).
+ */
+const issueAttrs = (type: IssueEventType, login?: string) =>
+  toEventDataAttributes({
+    scope: 'issue',
+    type,
+    category: ISSUE_TAXONOMY[type].category,
+    visibility: ISSUE_TAXONOMY[type].visibility,
+    actorType: login ? actorTypeForLogin(login) : undefined,
+  })
+
 /**
  * The Closed event group — `IssueTimeline.eventClosed` (audit § 2).
  *
@@ -118,7 +137,7 @@ export const EventClosed = () => (
     {/* Closed as completed */}
     <VariantSection label="Closed as completed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('closed', 'monalisa')}>
           <Timeline.Badge variant="done">
             <Octicon icon={CheckCircleIcon} />
           </Timeline.Badge>
@@ -139,7 +158,7 @@ export const EventClosed = () => (
           (portable for docs copy-paste; matches production `TimelineRow`). */}
     <VariantSection label="Closed as not planned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('closed', 'monalisa')}>
           <Timeline.Badge
             style={
               {
@@ -165,7 +184,7 @@ export const EventClosed = () => (
     {/* Closed via pull request */}
     <VariantSection label="Closed via pull request">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('closed', 'monalisa')}>
           <Timeline.Badge variant="done">
             <Octicon icon={CheckCircleIcon} />
           </Timeline.Badge>
@@ -185,7 +204,7 @@ export const EventClosed = () => (
     {/* Closed via commit */}
     <VariantSection label="Closed via commit">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('closed', 'monalisa')}>
           <Timeline.Badge variant="done">
             <Octicon icon={CheckCircleIcon} />
           </Timeline.Badge>
@@ -210,7 +229,7 @@ export const EventClosed = () => (
           equivalent for github-ui's `ProjectV2` closer link. */}
     <VariantSection label="Closed via project">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('closed', 'monalisa')}>
           <Timeline.Badge variant="done">
             <Octicon icon={CheckCircleIcon} />
           </Timeline.Badge>
@@ -233,7 +252,7 @@ export const EventClosed = () => (
           composed here from Primer primitives. */}
     <VariantSection label="Closed as duplicate">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('closed', 'monalisa')}>
           <Timeline.Badge
             style={
               {
@@ -265,7 +284,7 @@ export const EventClosed = () => (
     {/* Closed with no state reason */}
     <VariantSection label="Closed (no reason)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('closed', 'monalisa')}>
           <Timeline.Badge variant="done">
             <Octicon icon={CheckCircleIcon} />
           </Timeline.Badge>
@@ -293,7 +312,7 @@ export const EventState = () => (
     {/* Reopened — open (green) badge via useIssueState (ReopenedEvent.tsx) */}
     <VariantSection label="Reopened">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('reopened', 'monalisa')}>
           <Timeline.Badge variant="open">
             <Octicon icon={IssueReopenedIcon} />
           </Timeline.Badge>
@@ -310,7 +329,7 @@ export const EventState = () => (
           plain inline Link (the audit shows it bold; live code is canonical). */}
     <VariantSection label="Transferred">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('transferred', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LinkExternalIcon} />
           </Timeline.Badge>
@@ -329,7 +348,7 @@ export const EventState = () => (
     {/* Pinned */}
     <VariantSection label="Pinned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('pinned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PinIcon} />
           </Timeline.Badge>
@@ -345,7 +364,7 @@ export const EventState = () => (
     {/* Unpinned */}
     <VariantSection label="Unpinned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('unpinned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PinIcon} />
           </Timeline.Badge>
@@ -362,7 +381,7 @@ export const EventState = () => (
           the resulting discussion by number. */}
     <VariantSection label="Converted to discussion">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('converted_to_discussion', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={CommentDiscussionIcon} />
           </Timeline.Badge>
@@ -378,6 +397,7 @@ export const EventState = () => (
     {/* Converted from draft */}
     <VariantSection label="Converted from draft">
       <Timeline aria-label="Issue timeline">
+        {/* 'Converted from draft' has no ISSUE_TAXONOMY leaf (a draft-conversion verb the Issues catalog excludes); left untagged. */}
         <Timeline.Item>
           <Timeline.Badge>
             <Octicon icon={IssueDraftIcon} />
@@ -407,7 +427,7 @@ export const EventReferences = () => (
           open PR state icon inline before the PR title). */}
     <VariantSection label="Linked pull request">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('connected', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={CrossReferenceIcon} />
           </Timeline.Badge>
@@ -431,7 +451,7 @@ export const EventReferences = () => (
           icon is behind the live code here. */}
     <VariantSection label="Unlinked pull request">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('disconnected', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={GitPullRequestIcon} className={classes.BadgeIconOpen} />
           </Timeline.Badge>
@@ -451,7 +471,7 @@ export const EventReferences = () => (
           inline (showAgoTimestamp={false}) and the commit card is sub-content. */}
     <VariantSection label="Single commit reference">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('referenced', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={GitCommitIcon} />
           </Timeline.Badge>
@@ -482,7 +502,7 @@ export const EventReferences = () => (
     {/* Multiple commit references — same event, pluralized copy + N cards. */}
     <VariantSection label="Multiple commit references">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('referenced', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={GitCommitIcon} />
           </Timeline.Badge>
@@ -538,7 +558,7 @@ export const EventDuplicates = () => (
           IssueLink uses the open (green) state icon. */}
     <VariantSection label="Marked as duplicate">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('marked_as_duplicate', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={DuplicateIcon} />
           </Timeline.Badge>
@@ -562,6 +582,7 @@ export const EventDuplicates = () => (
     {/* Marked <canonical> as a duplicate of this issue — no right controls. */}
     <VariantSection label="Marked as canonical">
       <Timeline aria-label="Issue timeline">
+        {/* 'Marked as canonical' has no ISSUE_TAXONOMY leaf (only 'marked_as_duplicate' exists); left untagged. */}
         <Timeline.Item>
           <Timeline.Badge>
             <Octicon icon={DuplicateIcon} />
@@ -584,6 +605,7 @@ export const EventDuplicates = () => (
     {/* Unmarked this as a duplicate of <canonical>. */}
     <VariantSection label="Unmarked as duplicate">
       <Timeline aria-label="Issue timeline">
+        {/* 'Unmarked as duplicate' has no ISSUE_TAXONOMY leaf (only 'marked_as_duplicate' exists); left untagged. */}
         <Timeline.Item>
           <Timeline.Badge>
             <Octicon icon={DuplicateIcon} />
@@ -605,6 +627,7 @@ export const EventDuplicates = () => (
     {/* Unmarked <canonical> as a duplicate of this issue. */}
     <VariantSection label="Unmarked as canonical">
       <Timeline aria-label="Issue timeline">
+        {/* 'Unmarked as canonical' has no ISSUE_TAXONOMY leaf (only 'marked_as_duplicate' exists); left untagged. */}
         <Timeline.Item>
           <Timeline.Badge>
             <Octicon icon={DuplicateIcon} />
@@ -638,7 +661,7 @@ export const EventModeration = () => (
     {/* User blocked (permanent) */}
     <VariantSection label="User blocked">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('user_blocked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -654,7 +677,7 @@ export const EventModeration = () => (
     {/* User temporarily blocked */}
     <VariantSection label="User temporarily blocked">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('user_blocked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -670,7 +693,7 @@ export const EventModeration = () => (
     {/* Comment pinned — IssueCommentPinnedEvent.tsx links the pinned comment. */}
     <VariantSection label="Comment pinned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('comment_pinned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PinIcon} />
           </Timeline.Badge>
@@ -689,7 +712,7 @@ export const EventModeration = () => (
     {/* Comment unpinned */}
     <VariantSection label="Comment unpinned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('comment_unpinned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PinIcon} />
           </Timeline.Badge>
@@ -720,7 +743,7 @@ export const EventIssueTypes = () => (
     {/* Type added */}
     <VariantSection label="Issue type added">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('issue_type_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueOpenedIcon} />
           </Timeline.Badge>
@@ -750,7 +773,7 @@ export const EventIssueTypes = () => (
     {/* Type removed */}
     <VariantSection label="Issue type removed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('issue_type_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueOpenedIcon} />
           </Timeline.Badge>
@@ -780,7 +803,7 @@ export const EventIssueTypes = () => (
     {/* Type changed */}
     <VariantSection label="Issue type changed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('issue_type_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueOpenedIcon} />
           </Timeline.Badge>
@@ -840,7 +863,7 @@ export const EventIssueHierarchy = () => (
     {/* Sub-issue added (single) */}
     <VariantSection label="Sub-issue added (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('sub_issue_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTracksIcon} />
           </Timeline.Badge>
@@ -865,7 +888,7 @@ export const EventIssueHierarchy = () => (
     {/* Sub-issue added (multiple) — plural copy + N reference rows */}
     <VariantSection label="Sub-issues added (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('sub_issue_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTracksIcon} />
           </Timeline.Badge>
@@ -897,7 +920,7 @@ export const EventIssueHierarchy = () => (
     {/* Sub-issue removed (single) */}
     <VariantSection label="Sub-issue removed (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('sub_issue_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTracksIcon} />
           </Timeline.Badge>
@@ -922,7 +945,7 @@ export const EventIssueHierarchy = () => (
     {/* Sub-issues removed (multiple) */}
     <VariantSection label="Sub-issues removed (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('sub_issue_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTracksIcon} />
           </Timeline.Badge>
@@ -954,7 +977,7 @@ export const EventIssueHierarchy = () => (
     {/* Parent issue added (single) */}
     <VariantSection label="Parent issue added (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('parent_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTrackedByIcon} />
           </Timeline.Badge>
@@ -979,7 +1002,7 @@ export const EventIssueHierarchy = () => (
     {/* Parent issues added (multiple) */}
     <VariantSection label="Parent issues added (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('parent_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTrackedByIcon} />
           </Timeline.Badge>
@@ -1011,7 +1034,7 @@ export const EventIssueHierarchy = () => (
     {/* Parent issue removed (single) */}
     <VariantSection label="Parent issue removed (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('parent_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTrackedByIcon} />
           </Timeline.Badge>
@@ -1036,7 +1059,7 @@ export const EventIssueHierarchy = () => (
     {/* Parent issues removed (multiple) */}
     <VariantSection label="Parent issues removed (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('parent_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={IssueTrackedByIcon} />
           </Timeline.Badge>
@@ -1084,7 +1107,7 @@ export const EventDependencies = () => (
     {/* Blocked by (single) */}
     <VariantSection label="Blocked by (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocked_by_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1109,7 +1132,7 @@ export const EventDependencies = () => (
     {/* Blocked by (multiple) — count in copy + N rows */}
     <VariantSection label="Blocked by (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocked_by_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1141,7 +1164,7 @@ export const EventDependencies = () => (
     {/* Blocked by removed (single) */}
     <VariantSection label="Blocked by removed (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocked_by_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1166,7 +1189,7 @@ export const EventDependencies = () => (
     {/* Blocked by removed (multiple) */}
     <VariantSection label="Blocked by removed (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocked_by_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1198,7 +1221,7 @@ export const EventDependencies = () => (
     {/* Blocking (single) */}
     <VariantSection label="Blocking (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocking_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1223,7 +1246,7 @@ export const EventDependencies = () => (
     {/* Blocking (multiple) */}
     <VariantSection label="Blocking (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocking_added', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1255,7 +1278,7 @@ export const EventDependencies = () => (
     {/* Blocking removed (single) */}
     <VariantSection label="Blocking removed (single)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocking_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1280,7 +1303,7 @@ export const EventDependencies = () => (
     {/* Blocking removed (multiple) */}
     <VariantSection label="Blocking removed (multiple)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('blocking_removed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={BlockedIcon} />
           </Timeline.Badge>
@@ -1332,7 +1355,7 @@ export const EventIssueFields = () => (
     {/* Set text field */}
     <VariantSection label="Set · text">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TypographyIcon} />
           </Timeline.Badge>
@@ -1353,7 +1376,7 @@ export const EventIssueFields = () => (
     {/* Set number field */}
     <VariantSection label="Set · number">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={NumberIcon} />
           </Timeline.Badge>
@@ -1374,7 +1397,7 @@ export const EventIssueFields = () => (
     {/* Set date field */}
     <VariantSection label="Set · date">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={CalendarIcon} />
           </Timeline.Badge>
@@ -1395,7 +1418,7 @@ export const EventIssueFields = () => (
     {/* Set single-select field — value is a colored token */}
     <VariantSection label="Set · single select">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={SingleSelectIcon} />
           </Timeline.Badge>
@@ -1429,7 +1452,7 @@ export const EventIssueFields = () => (
     {/* Changed text field */}
     <VariantSection label="Changed · text">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TypographyIcon} />
           </Timeline.Badge>
@@ -1450,7 +1473,7 @@ export const EventIssueFields = () => (
     {/* Changed number field */}
     <VariantSection label="Changed · number">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={NumberIcon} />
           </Timeline.Badge>
@@ -1471,7 +1494,7 @@ export const EventIssueFields = () => (
     {/* Changed date field */}
     <VariantSection label="Changed · date">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={CalendarIcon} />
           </Timeline.Badge>
@@ -1492,7 +1515,7 @@ export const EventIssueFields = () => (
     {/* Changed single-select field */}
     <VariantSection label="Changed · single select">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={SingleSelectIcon} />
           </Timeline.Badge>
@@ -1523,7 +1546,7 @@ export const EventIssueFields = () => (
     {/* Cleared text field — no value */}
     <VariantSection label="Cleared · text">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TypographyIcon} />
           </Timeline.Badge>
@@ -1540,7 +1563,7 @@ export const EventIssueFields = () => (
     {/* Cleared number field */}
     <VariantSection label="Cleared · number">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={NumberIcon} />
           </Timeline.Badge>
@@ -1557,7 +1580,7 @@ export const EventIssueFields = () => (
     {/* Cleared date field */}
     <VariantSection label="Cleared · date">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={CalendarIcon} />
           </Timeline.Badge>
@@ -1574,7 +1597,7 @@ export const EventIssueFields = () => (
     {/* Cleared single-select field */}
     <VariantSection label="Cleared · single select">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={SingleSelectIcon} />
           </Timeline.Badge>
@@ -1591,7 +1614,7 @@ export const EventIssueFields = () => (
     {/* Rollup: updated only — multiple field updates collapsed into one row */}
     <VariantSection label="Rollup · updated">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TypographyIcon} />
           </Timeline.Badge>
@@ -1616,7 +1639,7 @@ export const EventIssueFields = () => (
     {/* Rollup: removed only */}
     <VariantSection label="Rollup · removed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TypographyIcon} />
           </Timeline.Badge>
@@ -1635,7 +1658,7 @@ export const EventIssueFields = () => (
     {/* Rollup: updated and also removed — combined row joined by "and also" */}
     <VariantSection label="Rollup · updated and removed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TypographyIcon} />
           </Timeline.Badge>
@@ -1687,7 +1710,7 @@ export const EventProject = () => (
     {/* Added to project */}
     <VariantSection label="Added to project">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('added_to_project', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TableIcon} />
           </Timeline.Badge>
@@ -1708,7 +1731,7 @@ export const EventProject = () => (
     {/* Removed from project */}
     <VariantSection label="Removed from project">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('removed_from_project', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TableIcon} />
           </Timeline.Badge>
@@ -1732,7 +1755,7 @@ export const EventProject = () => (
         strings are PLAIN TEXT (not bold). Both forms shown under one caption. */}
     <VariantSection label="Project status changed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TableIcon} />
           </Timeline.Badge>
@@ -1746,7 +1769,7 @@ export const EventProject = () => (
             <MutedTime date={new Date('2022-07-24T16:40:00Z')} href="#" />
           </Timeline.Body>
         </Timeline.Item>
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('project_field_changed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TableIcon} />
           </Timeline.Badge>
@@ -1786,7 +1809,7 @@ export const EventLabels = () => (
     {/* Label added */}
     <VariantSection label="Label added">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('labeled', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TagIcon} />
           </Timeline.Badge>
@@ -1815,7 +1838,7 @@ export const EventLabels = () => (
     {/* Label removed */}
     <VariantSection label="Label removed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('unlabeled', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TagIcon} />
           </Timeline.Badge>
@@ -1845,6 +1868,7 @@ export const EventLabels = () => (
         with "and" between them. */}
     <VariantSection label="Labels added and removed">
       <Timeline aria-label="Issue timeline">
+        {/* 'Labels added and removed' is one row representing two events (labeled + unlabeled); a single row cannot carry two event types, so left untagged. */}
         <Timeline.Item>
           <Timeline.Badge>
             <Octicon icon={TagIcon} />
@@ -1905,7 +1929,7 @@ export const EventTitle = () => (
     {/* Title changed */}
     <VariantSection label="Title changed">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('renamed', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PencilIcon} />
           </Timeline.Badge>
@@ -1940,7 +1964,7 @@ export const EventMilestones = () => (
     {/* Added to milestone */}
     <VariantSection label="Added to milestone">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('milestoned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={MilestoneIcon} />
           </Timeline.Badge>
@@ -1960,7 +1984,7 @@ export const EventMilestones = () => (
     {/* Removed from milestone */}
     <VariantSection label="Removed from milestone">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('demilestoned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={MilestoneIcon} />
           </Timeline.Badge>
@@ -1999,7 +2023,7 @@ export const EventAssignments = () => (
     {/* Self-assigned */}
     <VariantSection label="Self-assigned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('assigned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PersonIcon} />
           </Timeline.Badge>
@@ -2015,7 +2039,7 @@ export const EventAssignments = () => (
     {/* Assigned someone else — assignee is a bold link, no avatar. */}
     <VariantSection label="Assigned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('assigned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PersonIcon} />
           </Timeline.Badge>
@@ -2031,7 +2055,7 @@ export const EventAssignments = () => (
     {/* Assigned multiple — joined with "and". */}
     <VariantSection label="Assigned multiple">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('assigned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PersonIcon} />
           </Timeline.Badge>
@@ -2049,7 +2073,7 @@ export const EventAssignments = () => (
     {/* Self-unassigned */}
     <VariantSection label="Self-unassigned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('unassigned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PersonIcon} />
           </Timeline.Badge>
@@ -2065,7 +2089,7 @@ export const EventAssignments = () => (
     {/* Unassigned someone else */}
     <VariantSection label="Unassigned">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('unassigned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PersonIcon} />
           </Timeline.Badge>
@@ -2081,7 +2105,7 @@ export const EventAssignments = () => (
     {/* Unassigned multiple — joined with "and". */}
     <VariantSection label="Unassigned multiple">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('unassigned', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={PersonIcon} />
           </Timeline.Badge>
@@ -2118,7 +2142,7 @@ export const EventLockUnlock = () => (
         too heated). */}
     <VariantSection label="Locked (with reason)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('locked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LockIcon} />
           </Timeline.Badge>
@@ -2128,7 +2152,7 @@ export const EventLockUnlock = () => (
             <MutedTime date={new Date('2022-07-26T11:46:07Z')} href="#" />
           </Timeline.Body>
         </Timeline.Item>
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('locked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LockIcon} />
           </Timeline.Badge>
@@ -2138,7 +2162,7 @@ export const EventLockUnlock = () => (
             <MutedTime date={new Date('2022-07-26T11:47:00Z')} href="#" />
           </Timeline.Body>
         </Timeline.Item>
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('locked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LockIcon} />
           </Timeline.Badge>
@@ -2148,7 +2172,7 @@ export const EventLockUnlock = () => (
             <MutedTime date={new Date('2022-07-26T11:48:00Z')} href="#" />
           </Timeline.Body>
         </Timeline.Item>
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('locked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LockIcon} />
           </Timeline.Badge>
@@ -2164,7 +2188,7 @@ export const EventLockUnlock = () => (
     {/* Locked (no reason) */}
     <VariantSection label="Locked (no reason)">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('locked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LockIcon} />
           </Timeline.Badge>
@@ -2180,7 +2204,7 @@ export const EventLockUnlock = () => (
     {/* Unlocked — UnlockIcon badge (not LockIcon). */}
     <VariantSection label="Unlocked">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('unlocked', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={UnlockIcon} />
           </Timeline.Badge>
@@ -2211,7 +2235,7 @@ export const EventCommentDeleted = () => (
     {/* Comment deleted */}
     <VariantSection label="Comment deleted">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('comment_deleted', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={TrashIcon} />
           </Timeline.Badge>
@@ -2249,7 +2273,7 @@ export const EventCrossReferences = () => (
     {/* Mentioned from an issue */}
     <VariantSection label="Mentioned in an issue">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('cross_referenced', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LinkExternalIcon} />
           </Timeline.Badge>
@@ -2274,7 +2298,7 @@ export const EventCrossReferences = () => (
     {/* Mentioned from a pull request */}
     <VariantSection label="Mentioned in a pull request">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('cross_referenced', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LinkExternalIcon} />
           </Timeline.Badge>
@@ -2299,7 +2323,7 @@ export const EventCrossReferences = () => (
     {/* Linked a closing pull request */}
     <VariantSection label="Linked a closing pull request">
       <Timeline aria-label="Issue timeline">
-        <Timeline.Item>
+        <Timeline.Item {...issueAttrs('cross_referenced', 'monalisa')}>
           <Timeline.Badge>
             <Octicon icon={LinkExternalIcon} />
           </Timeline.Badge>