I wanted to expand all my entries in my Org file, to see how large it had gotten, so I looked up how to do it.
To expand all tabs (org-show-all)
C-u C-u Tab
To close tabs to the startup visibility of the buffer (org-set-startup-visibility)
C-u C-u C-u Tab
Tada!
https://orgmode.org/manual/Global-and-local-cycling.html
Original: https://toots.dgplug.org/@jason/110189523608103710