Which filesystems can be mounted in Home Assistant OS?

Hello!

Can someone point me to something where I can find informations which type of filesystem Home Assistant OS can use to mount locally (on a Raspberry Pi 4).
I think ext4 will be normally supported.
What I want to mount is a drive with a HFS+ filesystem, as the drive will be written on my Mac as a 1:1 copy. The drive should work as a media drive, so it only has to be mounted read only.