SOLVED - Problem caused by missing one asterisk (*) in a section title whilst updating MrOtherGuy’s Compact UE panel CSS to Fx 115… finger trouble/PEBCAK. Apologies, and many thanks for all the help. :)
Updating from Firefox 114 > 115 the Unified Extensions panel has notably increased in size by approx 30% even when using MrOtherGuy’s updated ‘compact_extensions_panel: make it work in Fx115’ CSS: https://github.com/MrOtherGuy/firefox-csshacks/blob/master/chrome/compact_extensions_panel.css
Additionally, attempting to reduce the icon size or line padding makes no difference whatsoever.
Has some underlying code changed in Firefox 115’s UI?
(The eagle-eyed may notice the RH image is actually from the not yet updated LibreWolf 114.0.2-1)
In your screenshot it seems like the icon for the each extension is quite a bit bigger in 115. That probably causes each row to be taller. When I tried the style you mentioned couple of days back though, the panel size remained the same as it was is 114. As in, I didn’t experience this issue with larger icons, but maybe I have missed something.