service/static-shim.md

@@ -111,6 +111,13 @@ used. To opt-out of Review Apps, define `SKIP_REVIEW_APPS: 1` in the
 The active environments linked to Review Apps can be listed by
 navigating to the project page -> Deployments -> Environments.
 
+Please note that Review Apps do not currently work for Merge Requests
+created from personal forks. This is because personal forks do not have
+access to the SSH private key required to deploy to the static mirror
+system, for security reasons. Therefore, it's recommended that web
+project contributors be granted `Developper` membership so they're
+allowed to push branches in the canonical repository.
+
 ## Working with a staging environment
 
 Some projects such as `blog.torproject.org` have a specific staging area