The following packages have unmet dependencies:
libc6-dev : Breaks: libgcc-8-dev (< 8.4.0-2~) but 8.3.0-6+rpi1 is to be installed
But this is indeed a known error. Same happened in several other cases:
- Issue with apt full-upgrade when upgrading to bullseye
- Failed to upgrade from Debian Buster to Bullseye - #10 by alleyu2
- Updating to Bullseye · Issue #4857 · MichaIng/DietPi · GitHub
- …
So worth it if it prevents users from some upgrade trouble. It is definitely a Buster package, and development headers, so safe to purge.