With the merge and the change to PoS, there will also be a shift towards PBS. As far as i have researched, any block builder can build blocks with transactions from the mempool.
How are these blocks then offered to the validators to be included? I have found mev-boost which can be run by a validator to select mev-optimized blocks from a certain relay, however i am wondering how this happens by default. How and where do block builders send their built blocks and from where do validators select a block to be proposed by default?
Are there any standard relays or is the consensus client offering functionalities to broadcast possible blocks from which validators can choose?