This is a three-phase plan to migrate Bitcoin to a new post-quantum cryptographic standard. In it, the authors suggest adopting the already proposed P2QRH output types and abandoning ECDSA/Schnorr signatures. The BIP requests a mandatory switch of cryptographic signatures due to concerns of ECDSA/Schnorr being vulnerable to future quantum computers.
I do not follow much about P2QRH but with what I have read, probably it will have larger signature than the current one which are not resistant to quantum computing. I mean both ECDSA and Schnorr. Hope it will not have significant effect on the mempool?
I like this proposal if the Phase C is part of it.