Hi everyone.

can't understand what exactly is stored on the device, judging from what I read on them.

What do I really want to know - what is stored on the device?
- The entropy
- Seed phrase (mnemonic)
- Master seed (bip39 seed)

It sounds reasonable to store master seed (bip39 seed) - it's not human readable, you can derive keys from it, it can be restored via mnemonic, yet it can't be used to generate addresses for some coins (doge coin for examlple) or use the passphrase (another question i have).
But as far as I understand, Trezor keeps the seed phrase in it.
So the question remains... Specifically I'm interested in how it's implemented in keystone, trezor, ledger and onekey.

Another question - passphrase.
To use it after the wallet is created - you need the seed phrase to be present on the device, right? otherwise how would you use it as a 13 / 25 words?

I'd appreciate the help a lot! struggling with the choice and understanding right now