Corrections to Members Manual
Under "Responding to an invitation to join a group", the second bullet, it should say "A personal note from the group owner or moderator who sent the invitation may be included in the text of the message."
Under "Joining subgroups", second sentence, it should say "A subgroup is a group within another group and will be a subset of the members of the parent (primary) group." Fourth sentence should say "If you join a group that has subgroups, the group’s owner or moderator will determine whether you may also be a member of any subgroups and invite or add you to them accordingly." Add fifth sentence, "You may also be allowed to join on your own, depending on group settings."
Under "Understanding Groups.io accounts" > "Overview", the Note: should say "... you will have a different Groups.io account associated with each email address."
Under "Logging in to your account" > "Logging in through Facebook or Google", it should be clarified that those may need to be enabled for your account in the "Setting or changing account login elements" section under "Setting account preferences and viewing account information". The "Setting or changing account login elements" section it should say "... select the applicable checkbox(es) ..."
Under "Setting website preferences for your account" > Set the number of items to display in lists on group web pages" there should be a Note that infinite scroll may not be usable on all page displays, such as databases and will revert to 20 items.
Under "Setting up two-factor authentication" there should be a Note that loss of the authentication code, such as when a device is reset to factory, will result in the inability to log in without contacting firstname.lastname@example.org.
I'm sure there will be more to come as I finish reading the manual. I realize that some of these are nit-picky, but believe the manual should be as clear as possible.
I'd also like to thank Nina and Mark for doing a great job in getting all of this information gathered up and organized. I've done similar jobs in the past and it's not an easy, nor trivial, thing to accomplish.