I actually didn't know about this port, so no. It was originally built on graphql-core, but I found it difficult to use as a base for higher-level abstractions (not to mention it really is a 1-to-1 port of the JS lib and is thus incredibly un-Pythonic), so everything was written from scratch, including the parser. (Hence why it's not fully spec-compliant yet—a few GraphQL language features are still not implemented.)

Well,if that’s the case I’m very interested in it. I have been maintaining a private fork of graphene for a while, with a desire to improve performance but I’m stymied by having to go through graphql-core.

All the python graphql libraries are based on it, so your work is going to be very valuable I expect.