diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2598907e..789de586 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -615,6 +615,12 @@ Every issue must include:
   `State/In Progress`, `State/Paused`, `State/In Review`, or `State/Completed`), a milestone
   is mandatory. If no appropriate milestone exists, discuss with the project owner before
   proceeding.
+- **Branch/Tag (Ref):** Every issue must have its Forgejo **branch/tag** field set to the
+  branch where work for the issue is being done. This is the `Ref` field on the issue form in
+  Forgejo — it is separate from the branch name documented in the issue body's Metadata
+  section, although both should match. Setting this field allows Forgejo to associate the
+  issue with the correct branch in its UI and link tracking. The field should be set when
+  work begins on the issue (i.e., when it moves to `State/In Progress` or later).
 - **Description:** The body of the issue must contain the following sections:
   - **Background and context:** Why does this issue exist? What is the motivation?
   - **Current behavior** (for bugs): What is happening now that is incorrect or undesirable?