Name?

SLUL2 isn't very good ;)

sunflower-lang
.sf  (but that is used for "signature files" in Java)
.sfl
sunflower is used for a LOT of things: some past game company, some wwii war operation, lots of bands/movies etc, kansas, etc.
helianthus (=sunflower greek genus name, helios+ánthos)

yellowstar-lang
starcircle-lang

starflower-lang

goua-lang (...but to similar to go)
winua-lang (maybe too similar to WinUAE? also, win sounds like windows)
rugoho-lang (seems to not be in use for anything, but maybe too strong?) fileext .rgh
    - but that becomes confusing in cyrillic (g/h is the same letter)
    - and then it could become bad.

sluk - but sounds like "slack" and most likely it's already used by a ton of UK-related things...