Depends on what what you consider "works with UI.X 2 for Material Design":Do you think that you will be able to release a version that works for UI.X 2 for Material Design?
This Add-on does manage Font Awesome fonts, this does also work with UI.X 2 if configured accordingly - the Add-on however does not manage Material Design Icon fonts.
This might be smth. that can be added ia a future major version, but due to limited time resources it will take quite some time.
I assume you are using Debian / Ubuntu (or another distribution based on Debian)?Also, I installed "apt install fonttools" but after installation I can't find any path to "pyftsubset".
"pyftsubset" should be somewhere in usr/bin, correct?
Usually pyftsubset should be
/usr/bin/pyftsubset, if it is not you'de have to find out where it is.
dpkg -L fonttoolsmight help you.