I note that in the current (1.2 build 165) version, in the Internet Radio Stations area - if one wants to add, say, this URL:
http://stream0.wfmu.org/freeform-best-available
it’s accepted, whereas this URL:
https://wfmu.org/listen.m3u?show=70361&archive=147153
which is for streaming the MP3 archive of this show
https://wfmu.org/playlists/shows/70361
yields this error:
The above archive-listen URL works fine as a stream URL in, say, VLC or iTunes.
Whether or not an archive-play URL should be entered as a radio station is another matter (and I’d admit that ideally one wouldn’t go there, and I hope the the Roon boffins have thought up an elegant way to handle this class of problem); but in the meantime there’s no way at all to stream WFMU archives (and I assume almost certainly other quirky but valid stream URLs) via Roon, and it’d be nice if it were possible.