Call recording functionality within the Dialer app using modern Android storage with recordings stored in Recordings/Call Recordings and no restrictions based on region or special cases like playing a recording tone (users are still responsible for complying with their local laws).
users are still responsible for complying with their local laws
I'm assuming Google has the feature implemented in such a way that the user can't violate wiretapping laws (without otherwise interfering with the OS in some way), which is actually really significant because that eliminates a lot of the grey area that users of these ROMs and other apps generally operate in.