GitHub supports asm to certain degree but definitely not the .6502 extension (is it the standard choice?).
I only ever did a clear screen or similarly simple programs in asm but I believe 6502 was a popular one. I think it was supported on both my TSR-80 and my first IBM PC.
Off-topic but anyone know a way to have Github recalculate these stats for idle projects without needing to re-commit stuff? I have one repo which says 99% Mathematica which is so far from the truth (there is no Mathematica code whatsoever.)
If it reports wrong, a recalculation likely won't help, you need to workaround/fix the underlying reason why it reports it wrong.
For example, it doesn't count document-type files by default; you need to modify `.gitattributes` files to override that.