Add documentation on the compliance dashboard drawer

doc/user/compliance/compliance_dashboard/index.md

@@ -22,6 +22,22 @@ To access the Compliance Dashboard for a group, navigate to **{shield}** **Secur
 NOTE:
 The Compliance Dashboard shows only the latest MR on each project.
 
+## Merge request drawer
+
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/299357) in GitLab 14.1.
+> - It's [deployed behind a feature flag](../../feature_flags.md), disabled by default.
+> - It's disabled on GitLab.com.
+> - It's not recommended for production use.
+> - To use it in GitLab self-managed instances, ask a GitLab administrator to [enable it](#enable-or-disable-merge-request-drawer).
+
+When you click on a row, a drawer is shown that provides further details about the merge
+request:
+
+- Project name and [compliance framework label](../../project/settings/index.md#compliance-frameworks),
+  if the project has one assigned.
+- Link to the merge request.
+- The merge request's branch path in the format `[source] into [target]`.
+
 ## Use cases
 
 This feature is for people who care about the compliance status of projects within their group.
@@ -84,3 +100,28 @@ the dropdown next to the **List of all merge commits** button at the top of the
 NOTE:
 The Chain of Custody report download is a CSV file, with a maximum size of 15 MB.
 The remaining records are truncated when this limit is reached.
+
+## Enable or disable merge request drawer **(ULTIMATE SELF)**
+
+The merge request drawer is under development and not ready for production use. It is
+deployed behind a feature flag that is **disabled by default**.
+[GitLab administrators with access to the GitLab Rails console](../../../administration/feature_flags.md)
+can enable it.
+
+To enable it:
+
+```ruby
+# For the instance
+Feature.enable(:compliance_dashboard_drawer)
+# For a single group
+Feature.enable(:compliance_dashboard_drawer, Group.find(<group id>))
+```
+
+To disable it:
+
+```ruby
+# For the instance
+Feature.disable(:compliance_dashboard_drawer)
+# For a single group
+Feature.disable(:compliance_dashboard_drawer, Group.find(<group id>)
+```