Kind of related, but long ago I wrote a locator-based system inspired by Trackmania. The idea was that every DLC would have associated .loc file, which is just a plain text with download link. If you are in a room and someone uses a DLC you are missing (like map theme used by host, or a hat used by any team), you'd get a warning and option to download it. It was pretty much finished, but never got approved and then I forgot about it and deleted my repo, so it's gone.

Huh... don't remember that one. Was that before we had the draft repo? 'cause it should not have gotten lost if pushed there.

But yeah, arbitrary link locations would be a problem. perhaps ones relative to trustworthy places..

Is more about the community content that should be included in game as steam dlc