Web editor for Keith McMillen Instruments BopPad, hacked up a tiny bit for Linux support.
Official editor lives here.
Just clone/download the project and open editor.html directly from disk in your browser.
Tested in Arch Linux.
Works using Chromium (tested with 111.0.5563.110).
Works using Firefox (tested with 111.0.1) but not when loaded via file://. Even though this should be a secure context, Navigator.requestMIDIAccess() is not available. A workaround for Firefox is to serve the editor locally. An easy way to do this if you have Python 3 installed is to run the following from inside the project directory:
python -m http.server
Then visit http://localhost:8000/editor.html in Firefox to use the editor.