Hint (Chrome / Edge):
after clicking "1) Setup", choose "Your entire screen" and tick "Share system audio",
or share a tab and enable "Share tab audio".
Safety / performance:
for computer safety, record a maximum of about 1 hour at a time
and close unused tabs and apps before long recordings.
This app works best on a computer with 16 GB RAM or more
and is theoretically able to record up to 2 hours, but very long sessions can be harder for the browser to handle.
Idle. Click "1) Setup" and follow the hints above.