Everything needed to make Firefox useable again!
/* Enable userChrome.css in Profile Directory chrome */
toolkit.legacyUserProfileCustomizations.stylesheets true
/* Enable old Compact Mode again */
browser.compactmode.show true
/* Disable Trim URL Bar both Protocol and trailing / */
browser.urlbar.trimHttps false
browser.urlbar.trimURLs false
/* Disable all Hover Tab Preview functions */
browser.tabs.hoverPreview.enabled false
browser.tas.hoverPreview.showThumbnails false
/* Disable/Hide ALL 'HTML5 Video Fullscreen Message' related things */
full-screen-api.transition-duration.enter 0 0
full-screen-api.transition-duration.leave 0 0
full-screen-api.transition-duration.timeout 0
full-screen-api.warning.delay 0
full-screen-api.warning.timeout 0
The first two are DEFAULTS in LibreWolf it seems!
/* Disable ALL Smoth Scrolling */
general.smoothScroll false
general.smoothScroll.lines false
general.smoothScroll.mouseWheel false
general.smoothScroll.msdPhysics.enabled false
general.smoothScroll.pixels false
general.smoothScroll.scrollbars false
toolkit.scrollbox.smoothScroll false
Some of these might be Disabled by Default but just check them all anyway!
*** Disclaimer : ***
Everything you can find in the userChrome.css can be found elsewhere on the web!
So if you recognize your own code by any chance : Thank you for helping others with their Mozilla Firefox related modifications! ;)