Add doc for remove query params defaults

content/terms/how-to/apply-filters.md

@@ -109,9 +109,11 @@ For filters that don’t require parameters, add the filter name as a string:
 }
 ```
 
+Built-in filters declared this way use their default parameters. For example, `removeQueryParams` alone removes the well-known tracking parameters described in its [reference]({{< relref "terms/reference/built-in-filters/#ref-removequeryparams" >}}).
+
 ### Filter with parameters
 
-For filters that take parameters, use an object format, for example with the built-in filter `removeQueryParams` to remove query parameters from URLs:
+For filters that take parameters, use an object format, for example with the built-in filter `removeQueryParams` to choose which query parameters to remove from URLs:
 
 ```json
 {

content/terms/reference/built-in-filters.md

@@ -8,9 +8,24 @@ This reference details all available built-in [filters]({{< relref "terms/explan
 
 {{< refItem
     name="removeQueryParams"
-    description="Removes specified query parameters from URLs in links and images."
+    description="Removes query parameters from URLs in links and images. Without parameters, removes well-known tracking parameters such as `utm_source` or `fbclid`, listed in the [engine source code](https://github.com/OpenTermsArchive/engine/blob/main/src/archivist/extract/exposedFilters.js). Declaring parameters replaces this default list."
 >}}
 
+With the default parameters:
+
+```json
+"filter": [
+    "removeQueryParams"
+]
+```
+
+```diff
+- <p>Read the <a href="https://example.com/example-page?utm_source=OGB&fbclid=IwAR2xK9&lang=en">list of our affiliates</a>.</p>
++ <p>Read the <a href="https://example.com/example-page?lang=en">list of our affiliates</a>.</p>
+```
+
+With explicit parameters:
+
 ```json
 "filter": [
     {
@@ -24,4 +39,38 @@ This reference details all available built-in [filters]({{< relref "terms/explan
 + <p>Read the <a href="https://example.com/example-page?lang=en">list of our affiliates</a>.</p>
 ```
 
+To keep the default parameters and remove additional ones, declare the filter twice, as filters are applied in order:
+
+```json
+"filter": [
+    "removeQueryParams",
+    {
+        "removeQueryParams": ["ref"]
+    }
+]
+```
+
+```diff
+- <p>Read the <a href="https://example.com/example-page?utm_source=OGB&ref=footer&lang=en">list of our affiliates</a>.</p>
++ <p>Read the <a href="https://example.com/example-page?lang=en">list of our affiliates</a>.</p>
+```
+
+{{< /refItem >}}
+
+{{< refItem
+    name="convertSpacesToStandard"
+    description="Replaces Unicode space separators, such as non-breaking spaces or narrow no-break spaces, with a regular space in text content."
+>}}
+
+```json
+"filter": [
+    "convertSpacesToStandard"
+]
+```
+
+```diff
+- <p>Read the list of our&nbsp;affiliates.</p>
++ <p>Read the list of our affiliates.</p>
+```
+
 {{< /refItem >}}