Steps to reproduce:

1. Install 1.20.1
2. Install ANY forge for 1.20.1.
3. Install ANY framework mod and Curios for 1.20.1.
4. Install ANY version of backpacked for 1.20.1.
5. Go to controls tab.
   ???
   NO WAY THE KEY IS MISSING
   Additional steps:
6. Give up.
7. Try to add key_key.backpack:key.keyboard.o from 1.19.4 to 1.20.1 options.txt
8. Restart Minecraft
9. The key is still missing.
10. Give up.
    
    

Duplicate of #178, but experiencing the same issue here.

Try to add key_key.backpack:key.keyboard.o from 1.19.4 to 1.20.1 options.txt
Restart Minecraft
The key is still missing.

So it didn't help.