Please check this https://github.com/perl6/doc/commit/f6df30a8fc
It's going to be soon in the docs (they are updated every 5 minutes if there are changes), however a general discussion of when to use "but" and when to use "does" is still missing. I'm working towards it in this page https://docs.perl6.org/language/traits, but there's still a long way to go. JJ
