Part of the Jellyfin Project
The Jellyfin Cast Web Receiver is the frontend used when casting to a Google Cast capable device. It is used by default when casting from the Jellyfin Android app or Jellyfin web client.
A stable and unstable version of this app are already included in the Jellyfin server. There is no need to separately install this project. To host your own version (for developing) see CONTRIBUTING.md.
The stable version is the latest released version. unstable is updated automatically from the master branch.
This is a web receiver as defined in the Google Cast architecture.
As soon as you press the "cast" button on your client this application will start on you cast-capable device and handle playback functionality.
Anything related to your non-cast device (e.g. your phone, browser, other device) or anything about the inclusion of casting for a specific client (e.g. casting from the iOS app).
Any issues/features related to that: check the respective repository.
First check if the issue is actually Google Cast related. So answer the question:
"Can I reproduce the issue on any other way then when casting to a Google Cast capable device?"
If yes: The issue probably lies somewhere else. If no: Open an issue on GitHub.
Jellyfin allows switching between a stable and unstable version of the client. Go the client of your choice and: user -> settings -> playback -> Google Cast version.
Note that this setting is set per-user.