Although I've broadcasted many transactions via testnet with RBF opted-in (
--rbf true), yet, given different
incentives present among the miners of the testnet and of the mainnet, my experience so far does not seem very helpful when it comes to grasping firmly how RBF works in Electrum.
So far I've always broadcast them with 1 sat/byte. I most
cases they were picked up by miners with this fee. A couple of times I noticed a slight discrepancy between the fee that I did broadcast (always 1 sat/byte) and the fee (1.2-1.3 sat/byte) that was shown in the blockchain explorer. Such minor discrepancies suggest to me that Electrum somehow automates the process of bumping the fee up when needed.
Does Electrum handle incrementing the fee for me or do I have to manually bump the fee up? If the latter is the case, can the fee bumping be done from the terminal (i.e. without GUI)? If the logic of the wallet automates the RBF process, how does it look like exactly? How many blocks does it wait until it increments the fee? By what factor is the fee increased? I have not found any information that would answer my questions in Electrum's documentation.