I guess if a dataset is APF protected and when you try to edit it, BROWSE will be substituted automatically.
on a professional forum guessing is just a waste of time for everybody.
( even worse when the guess is completely wrong )
instead of guessing better spend time meditating on
Introduction to the New Mainframe: z/OS Basics
and on the whole series of
ABCs of z/OS System Programming
to save You from guessing here is the link to the first volume of the series