1 - Ownership of the activity
It's your ownership of the activity that you're giving to another person. The recipient of the transfer therefore becomes the owner in your place and obtains all the rights to the activity.
2 - Which activities?
You can transfer all activities in this way (Board, Quiz, Memo, Survey, Mission, etc.).
You can also transfer a Network. In this case it is only the ownership of the Network that is transferred and not that of the activities published on it, which must be transferred separately if necessary.