At the top you can see it's Facric Loader 0.13.3.

Loading Fabric Installer: 0.10.2
OS_ID: linux-amd64
Installing
Installing 1.17.1 with fabric 0.13.3
Creating profile

I have a Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz computer and runs on Ubuntu 20.04.3 LTS.

This mod also needs fabric-api!
Now it is working great!

yeah the "fabric" you see in the error report is actually "Fabric API" i forgot to add it as a dependency on curseforege, fixed now

thanks for the report