BIP118 (SIGHASH_NOINPUT) vs. ANYPREVOUT

[Bitcoin]

BIP118 (SIGHASH_NOINPUT) vs. ANYPREVOUT

I understand the motivation for SIGHASH_NOINPUT - it would help with offchain payment channels. It was proposed already in the Lightning paper but Eltoo will effectively work just with something like that. But what exactly is the ANYPREVOUT BIP about? It seems like some extension to be used with taproot scripts. But I don't seem to get why you need a special public key type and chaperone signatures. Can anyone explain this part in plain english please?

Source: BIP118 (SIGHASH_NOINPUT) vs. ANYPREVOUT