MinecraftForge
Rarities are not extensible
Name entails. I'm making this issue to track whatever progress could be done on this, as a follow-up to the closing of #10009.
can I do some work on this? I looked at the old ticket for context and do you know what files I would need to work on for this issue/feature?
Look at how rarities were extended in older versions, and try and mimic how it was done there. The last version it was working in was either 1.20.4 or 1.20.1, do check which one it was.
You should be comfortable enough with your IDE of choice to be able to find the files yourself. In IntelliJ, you can double-press the shift key and it will bring up a search window that you can use to search for class names. Start there and see what you're able to do.