HCP, Thank you for your knowledge. I would like to know if this is the same type of system that Blockchain.com uses? Thank you for your help.
No... Apparently, they have some sort of bespoke system going on. Plus, they claim that they are NOT a custodial wallet... they only store an "encrypted" copy of your wallet data which is then downloaded and decrypted within your browser on the client side.
They do not control your private keys/seeds etc.