mention on-disk files

howto/gitlab.md

@@ -655,6 +655,15 @@ reliability and scalability of the service, but the service could be
 used for small sites at this stage. See the [GitLab pages installation
 instructions](#gitlab-pages-installation) for details on how this was setup.
 
+Note that the pages are actually on disk, in
+`/var/opt/gitlab/gitlab-rails/shared/pages/GROUP/.../PROJECT`, for
+example the status site pipeline publishes to:
+
+    /var/opt/gitlab/gitlab-rails/shared/pages/tpo/tpa/status-site/
+
+Maybe this could be abused to act as a static source in the static
+mirror system?
+
 ## Issues
 
 [File][] or [search][] for issues in the [gitlab project][search].