[snowwrestler]

Just a bit lower on the same page:

> When iCloud Backup is turned on, everything inside it is end-to-end encrypted, including the Messages in iCloud encryption key.

Meaning that Apple does not actually have access to that key, because it is encrypted before being saved to their servers.

[modeless]

This is misleading, again. The paragraph you quoted only applies with optional "Advanced Data Protection". Advanced Data Protection is off by default. In the default state Apple does have access to the Messages in iCloud keys in iCloud Backup, as I said.

[alphabettsy]

Yep.

Table is here: https://support.apple.com/en-us/102651