Hayagriva YAML Reader
As far as I understood the typst team implemented their own YAML bibliography format. While I am not personally interested in using it, pandoc could ship with a reader for their bibliography format.
I have not had a good look on their format spec, so I am currently not sure how easy it would be to implement. I'm also not sure what the opinions on a Hayagriva YAML reader are, as I could not find any public discussions about that. However, if you think that sounds like a good idea, I could also help with implementing it.
I wonder how widely used this is. Typst has now also implemented CSL bibliographies, I believe, and I suspect it will make more sense for people to use this standard and powerful system.
Typst does not support CSL bibliography data, only CSL bibliography/citation styles. The Hayagriva YAML format is not compatible with CSL-JSON or CSL-YAML. It is optimized for ease of entry and tight integration with Typst, not for standards-based interoperability. See this Typst issue.
Thanks for the clarification on this.