How to find details about very first block mined for any crypto?
If you have an altcoin's node software and that software is based off of Bitcoin Core, then you can use the following RPC commands to get information about the genesis block:

getblockhash 0


This will get you the hash of the genesis block. Take that hash and do

getblock &lt;hash&gt;


This will give you all of the information about the genesis block.