As far as I understand, there is a standard that describes what address types an extended private key or extended public key is intended to derive and it works as such:

• xpriv/xpub => Legacy address (1...)
• ypriv/ypub => nested SegWit address (3...)
• zpriv/zpub => native SegWit address (bc1q...)

So regarding this, I have 2 questions:

1. What is the name or BIP number of this standard?
2. What does an extended public key look like, that is intended to be used for P2TR addresses (bc1p...)?