[ljm]

Yeah, I feel like there was a bit of an expectation mismatch around that. `using` makes a lot more semantic sense than `include` or `extend` in a lot of cases but it didn’t play out that way and we’re still living with the unusual convention of making ‘x-able’s and writing ‘concerns’. Not to mention that they were file-scoped and not lexical in their first version so had limited utility for library devs.

As far as I know the teething issues around refinements are ironed out but they remain an obscurity.