[08:01] <sakrecoer[bpist]> <Eickmeyer "Peter Nebelong: You also need th"> they are not? i'm using them on 21.04 without any problem...
[08:02] <sakrecoer[bpist]> though, i did upgrade from 20.10
[08:06] <sakrecoer[bpist]> Peter Nebelong the blender that is bundled with Ubuntu studio does not have cuda (removed by debian because non-free) 
[08:06] <sakrecoer[bpist]> pretty sure you will be able to emable it if you run a version from blender.org
[08:10] <sakrecoer[bpist]> of course, you will need the proprietary Nvidia driver. (found under "additonal drivers" in "Software sources" which you will find in the settings of the app "Discover") 
[08:15] <sakrecoer[bpist]> so yes, cuda repos are not available in 21.04, but you don't need them since they are packaged in the blender for linux that blender foundation is shipping
[19:05] <Eickmeyer> sakrecoer[bpist]: Good to know, but if one wants the CUDA repo they need to be on focal since it only supports that.