demm KaOS is not Debian based, does not use the .deb package format or package manager. To add packages you miss to your install, see: https://kaosx.us/docs/package/
Fabio demm The problem is that Google music manager is provided just as deb and rpm package and I don't know where is the source
zynex Fabio You can use AUR's PKGBUILD to install it. You find it at https://aur.archlinux.org/packages/google-musicmanager. Download the PKGBUILD file, and run makepkg -si. You might have to compile some dependencies (not sure if all is in the repo, some might have a different name here).