Re: Does Electrum record the date a transaction was sent to the mempool?
the closest I can think of would be the "received time" shown for a transaction on blockchain.com
The time listed there is the timestamp of the block.
Check TransID: 0753895afa2c2f76b6a383a4ec2fe8efa87c583588dcb5fe7b9154dd50b57680
Received Time: 2021-01-24 18:06
Block was: 667422
BlockTime was: 2021-01-24 18:56
Note: it's possible that for some transactions, blockchain.com might only see the transaction for the first time when it is included in a block... so you might get received time == block time... or it might be that the transaction was received a few seconds before the block was mined etc (as the timestamp is only to the nearest minute).