I am unsure of if they are now in the execution clients, or in the consensus client, or a combination of the two. I am specifically looking to find where a block would be marked invalid if there is not enough ether + gas in the account that tries to send a transaction. All the execution clients have this as part of their TXPOOL code, but I can't seem to find any other place it is validated, so if such a transaction sneaks in could it end up being valid? I do see a lot of code about verifying headers but I am not seeing any details such as "here we check the nonce" and "here we check that the account has enough eth".
Consensus rules aren't set in a file , like you normally do in a config for a firewall or something like that. Neither they are set as an
if condition to check for some flags.
They are implemented in a module called "Consensus"