All releases of Plasma don't have a codenames, it feels that it's don't have a individuality, why not to start using a codenames of releases on Plasma 6 branch? Just need to determine the theme of codenames, for example, it could be to Art theme, it could name of Music Album, it may be in honor to Artist, Films Creator or Musician, even to use the names of specific works (for example Picture Name or Name of Song).
Here a couple of examples:
Plasma 6.0 "Discovery" (like the album by Daft Punk)
Plasma 6.1 "Bowie" (like David Bowie)