How to recover public key with ECDSA?

[RobinLinus]

Any suggestions on how to implement public key recovery with WebCrypto ECDSA?

How is (r,s) encoded in the output buffer of sign?
Is it just r = [0,32) and s = [32,64) for curve = P-256 (docs) ?

Seams like elliptic.js implements the recovery and it should be possible to import the recovered public key via jwk back into WebCrypto ...