This is a pretty simple algo: it looks at if there is another proof with a peer associated which is positionned before the candidate for each of its utxos, the this proof cannot be made a peer. Since the proof pool is expected to store conflicting proofs and orphan proofs, there might be proofs with better properties which are not suitable as peers, so the candidate can be the suitable as a peer even if not at first position for each utxo.

Ref T1854.

Depends on D10492.