Wondering out loud…
So, Mastodon doesn’t support the “listen” activitypub verb.
Does that mean that Mastodon strips it from the API results, so you won’t see it in @IceCubesApp or @phanpy ? Or does it just mean that Mastodon strips it from its own UI?
If it’s still visible in the API results, then that means you could still do some fun things with the “listen” verb in third-party apps. Including podcast apps. And all the while, not flooding the fediverse with “listen” activities (especially for music listening).