Extracted from #408 (comment)

On the other side of this, what about making a namespace that actually is intentionally similar to PEP 557 dataclasses and fields, and just has a thin adapter layer between field and attr.ib, etc? How much incompatibility is there beyond the names? Isn't attrs mostly a superset?

It would be good for migrating from large codebases where dataclasses are already used, or for pythonistas who want codebases/apis that stick close to the PEP specifications where possible.