I’m guessing that this is because of the shift from KDecoration2 to KDecoration3. There’s a pull request at the klassy github - Naive bump from KDecoration2 to KDecoration3 for Plasma 6.3 by Foxinatel · Pull Request #178 · paulmcauley/klassy · GitHub, and also the same fixes with kdesrc-build instructions at Klassy for development version of Plasma | Ivan Čukić
2 Likes