Debian packages: stuff (trunk)

Gamescope 3.15.14 (latest; incl. non-merged polaris-gpu-fix)
mesa 25 (latest, as tar; + -dev-packages as seperate tar)
Breeze Enhanced (Plasma 6.1+)
Kvantum (Plasma 6.2+)
Klassy (Plasma 6.21+)
Kiview