New comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/issues/24871#issuecomment-691535102

Comment:
Unfortunately, XBPS does not support optional dependencies. The `python3-PyQt5-svg` package is only required if the qt5 backend is used in matplotlib. Because this is a configuration option (and isn't even the default), forcing people to pull in or ignore this package isn't appropriate.

You'll just have to manually install `python3-PyQt5-svg` to support this backend.