It's been a while, actually, a year, since I last posted a log here...
The reason is that much work has been done on eXaDrums during that time. The GUI hasn't changed much, but the library has evolved quite a bit.
The first very important thing is a 'virtual instrument'. On the GUI side, it is called 'Virtual Pad', and this is how it looks:
Each instrument has its own button, so you can either use a mouse or tap your touchscreen to trigger it. If you're using a PC, you can assign shortcuts to the instruments (up to 2), so that they can be triggered by a keyboard.
This almost minor add-on was , in my opinion, necessary to have the packages (eXadrums and libexadrums) submitted to the debian repositories.
Both eXaDrums and libexadrums are available from debian sid (unstable) and bullseye (testing). In fact, they are also available from Ubuntu 19.10, and the next LTS release, 20.04.
Anyway, this should simplify exadrum's installation for debian and ubuntu users.
Hopefully, the next Raspbian release will also ship with exadrums in it's official packages!