Plasma-framework is a framework, which means it has a different release schedule from Plasma and other products that use its release cycle, such as the Breeze repo. This causes various problems, such as making it impossible to synchronize visual changes between the Plasma Breeze theme and the Breeze QWidgets theme, or change the filetype of the wallpaper (which lives in Breeze) because the Breeze Plasma theme's metadata.desktop file which specifies the filetype lives in plasma-framework.
I'd like to propose that the Breeze repo be made a framework, and then we would move the wallpaper and other Plasma stuff out of it and into the plasma-workspace LNF package or another repo aligned with the Plasma release schedule.