@jbz fwiw... i still use ​​ & love it. i disable or otherwise just don't use its #AI bullshit baggage. i enjoy using its new long-awaited #SplitTabs feature. i use the brilliant #FirefoxSecondSidebar project, giving me a #WebPanel second-sidebar more powerful & flexible than any of #Floorp, #Zen [before they removed it], & Vivaldi. i use the magnificent #TreeStyleTab AO for exquisite infinitely-nestable hierarchical tabs that blows FF's native vertical tabs, chromium's, Floorp's, Vivaldi's outta da water. I use the also magnificent #SimpleTabGroups AO to give me excellent #Workspaces capability. my #uBlockOrigin is in Advanced Hard Mode, & the many tens of thousands of dynamic filter rules i've cumulatively created over the years helps make day to day browsing simply lovely. I use custom #userChrome.css, #userContent.css, & user.js files to tailor my Nightly's UX & UI "just so".

every day for many many months now i read so many posts from peeps [rightly] complaining about "what the fuck is mozilla doing to us with this ai garbage?", but who then solicit or advocate jumping to another
#Gecko variant, or [& these ones really make me roll my eyes] say they're now going to chrome coz why not... ffs.

for years i have actively also used / tested all the browsers named above [except chrome, never that pig-swill, but chromium yes], & also
#librewolf, #waterfox, #tor ... & in all cases i find various UX & UI aspects that frustrate me so much that sooner or later i always return to my bespoke #FirefoxNightly .

for those willing & indeed interested in bothering, afaict we foxxers can still have our cake & eat it.

fwiw.
GitHub - rafaelmardojai/firefox-gnome-theme: A GNOME👣 theme for Firefox🔥

A GNOME👣 theme for Firefox🔥. Contribute to rafaelmardojai/firefox-gnome-theme development by creating an account on GitHub.

GitHub
GitHub - aminought/firefox-second-sidebar: A Firefox userChrome.js script that brings a second sidebar with web panels like in Vivaldi/Edge/Floorp but better.

A Firefox userChrome.js script that brings a second sidebar with web panels like in Vivaldi/Edge/Floorp but better. - aminought/firefox-second-sidebar

GitHub

J’ai fait une petite surcouche #css à mon #Thunderbird pour mieux voir mes mails non lus !

~/.thunderbird/$/chrome/userChrome.css

.card-layout[data-properties*="unread"] .card-container{ background: #32302f !important; }
C’est trop cool, car il y a un inspecteur pour l’UI de Thunderbird, du coup c’était hyper simple de trouver le sélecteur !

#Betterbird #userChrome

I've been using Firefox (Developer edition) with vertical tabs but using Sidebery, and it has worked great, but I think a Firefox update changed it so the Sidebery button would show/hide both together.

Work-around was adding the following in a userChrome.css (which I've never felt the need to really utilize before, for whatever reason)

sidebar-main {
display: none;
}

#Firefox #Sidebery #userchrome

I made a minimal firefox userStyle with a sidebar. Just when Firefox plans on releasing sidebar tabs.

But mine uses sidebery which supports tree style tabs.

#firefox #userChrome #css #linux

Take a look at it:
https://github.com/scientiac/scifox

GitHub - scientiac/scifox at immersive

A Minimalist Firefox userStyle. Contribute to scientiac/scifox development by creating an account on GitHub.

GitHub

Если ли же вам хочется лишь небольших исправлений в интерфейсе, то рекомендую посмотреть на этот репозиторий https://github.com/MrOtherGuy/firefox-csshacks/blob/master/chrome/combined_favicon_and_tab_close_button.css

Например, я пользуюсь стилем, который перемещает иконку закрытия вкладки на фавикон.

О том как настроить Firefox для таких манипуляций и разрабатывать стили: https://www.reddit.com/r/FirefoxCSS/wiki/index/tutorials/

#userchrome

firefox-csshacks/chrome/combined_favicon_and_tab_close_button.css at master · MrOtherGuy/firefox-csshacks

Collection of userstyles affecting the browser. Contribute to MrOtherGuy/firefox-csshacks development by creating an account on GitHub.

GitHub

Если вы впервые слышите о #userchrome в Firefox, то посмотрите, что умельцы с помощью него делают: https://firefoxcss-store.github.io

Скучаете по Windows 95? Нравится дизайн Safari или Arc? Легко!

FirefoxCSS Store

A curated list of Firefox userChrome.css Themes.

Не устраивает узкая адресная строка в Firefox? Не беда, исправляется одной строчкой #userchrome

#urlbar[open] { width: 80vw !important; }

I think my #userChrome.css for #firefox is done now. I am pretty content with how it looks. Not stealing screen estate as it did before.

If anyone want to do it themselves I'll attach my userChrome.

Basically here is what you do...

Enable userChrome.css customizations in latest Firefox versions:
Open about:config
Set toolkit.legacyUserProfileCustomizations.stylesheets = true

Find menu item ID:
Open developer tools (F12)
Open the settings (F1)
Check "Enable browser chrome and add-on debugging toolboxes"
Check "Enable remote debugging"
Open browser debugging (Ctrl-Alt-ShiftI), accept incoming connection
In the browser debugging click on options button (...) > Disable popup auto-hide
Open FF context menu
In the browser debugging use "Inspect Element" to find the victim menu item
E.g. the CSS selector for option "Copy Link" is:
#context-copylink

Create "userChrome.css":
Open FF profile: Help > Troubleshooting Information > Profile Directory
Create "chrome" folder
Create "userChrome.css"
Hide menu item by adding the found CSS selector to the userChrome.css:
#context-copylink {
display: none;
}

After adding all the desired menu items restart Firefox

source:
superuser.com/questions/1741879/edit-firefoxs-context-menus jaunsmotivs.blogspot.com/2018/08/how-to-remove-option-from-firefox.html
Edit Firefox's context menus

It was once possible to edit firefox's context menus by using various extensions - which no longer exist. Presumably firefox's APIs changed, so those extensions stopped working and were delisted. My

Super User