Yes, please treat this part with caution - it was put together on the base of what features Bluetooth 5.0, the specification, offers vs. what the Pi actually offers - I could not verify whether these features are present, as it was literally written at around 1 o'clock today in the morning. I apologize for any confusion!
"The new BCM2711 adds some new interface functions on ALT6 and ALT7:"
In fact, the new functions are spread across the existing ALT functions.
I will update the document with more information and accurate information, and repost.
@jamesh / @ Gordon : could you please inform us which Bluetooth 5.0 extensions are available in the Pi 4?