Hey there!
I make MIDI controllers and now starting to use Midi Mixer. I love it! I've been looking for something like this for a long time. But more specifically, I'm looking forward to something I couldn't find yet: a web browser MIDI mappable audio mixer with individual tab volume/mute controls. In MIDI Mixer, it could be something like having not only "Brave" as a single app for volume control, but all the internal tabs as well. I guess that the browser is probably rendering a "master" audio channel putting together all tab audio into a single signal, so that would be the main challenge. There are chromium-based plugins that let you control the tab volumes individually (like https://chrome.google.com/webstore/detail/volume-master/jghecgabfgfdldnmbfkhmffcabddioke), but no MIDI...
I understand that it might be a long shot on the MIDI-Mixer roadmap since it involves software-specific development, but is my main feature request 🙂
Keep up the good work!