If I'm not mistaken this flew under the radar for us at the old forums, despite the reverence we always show DoomEd:
https://archive.org/details/QuakeEd
An actual screenshot from Romero, with a jumpscare by OmniWeb 1.x in the dock:
(https://archive.org/download/QuakeEd/quaked1.gif)
The release is source-code-only, so you'll need to get some elbow grease ready before it'll work. The uploader says they tested it on emulated white hardware.
Man, I miss Omniweb so much. I loved that browser when I use it on OS X... before Safari existed. But this is really cool! I never knew about these editors... let alone that they existed for NeXT
This recent post https://rome.ro/quakes-player-speed-1 features the QuakeEd screenshot, and on the same site you can download the Quake map sources: https://rome.ro/resources
EDIT: Just found that we had John Romero's dump of QuakeEd (source) from 5/18/96 on the Peanuts archive NeXTSTEP/Games/action/
2232 Aug 24 1996 QuakeEd.README
394767 Aug 24 1996 QuakeEd.s.tar.gz