IETF RFC 9535 defines a proposed standard for JSONPath. Other resources:

• A partial Compliance Test Suite.
• Behaviours of various implementations can be checked in the comparison project. Please note that the JSONPath Reference Implementation referenced in the comparison project is stalled/archived and incomplete.
• At the time of writing, online sandboxes for RFC 9535 are available in C# and in Rust.
• For more background and comments on the status of the CTS and RI, see this this post (also here in the IETF blog).
• Public discussion occurs in the IETF JSONPath Working Group's mailing list (archive).

(See here for updates to this list of resources.)

Valid approaches for this project are to (a) implement the RFC in whole or in part, (b) document its behaviour relative to the RFC, and (c) do nothing.