This all doesn't really matter, though. The fact of the matter is that as soon as you install firmware with seed extraction capability, it's game over for your privacy and security.
Does anyone knows if it's possible to downgrade ledger firmware?
Maybe it would help a little to keep ledger always offline and connect it only with offline computer or smartphone when making transactions.
This can be temporary solution until ledger is replaced with some other device.
The fact that Ledger won't even tell you who that entity is or what security is being used to store your decryption key is highly suspect.
I am not defending ledger but I think they said this will be shared between three companies with different geo locations, France, United Kingdom and United States.
For encryption they are using Shamir Secret Sharing, that is a bit strange for me since they never supported that scheme in ledger before (unlike Keystone or Trezor).