I installed "Restart Browser" expecting a simple, convenient way to restart Firefox with a button click. Unfortunately, the add-on falls short. There is no button added to the Firefox menu, which is the main reason I got it in the first place. The only "button" available is buried in the add-on's options, and when you do find it, it does absolutely nothing! I tried restarting Firefox multiple times and even reinstalled the add-on to see if it would fix the issue, but no luck.

Overall, this add-on does not work as advertised, making it completely useless. Save yourself the hassle and look elsewhere.

Killed my workspaces at restart of Floorp Browser v11.14.1 fork.

I was hoping this tool would free up the live chat memory cache, but it didn't
Its NOT the full restart

I needed a simple 'button' to 'restart' Firefox. There is a 'real' button, and when you customize your toolbar (right click on toolbars), you can move the button and I put mine on the 'bookmark bar'. But you can leave it on the add-on toolbar and move it where you like it. As others have remarked, for me, no unusual or any 'pages' open to the authors site with option 2 or 3. If you choose an option which will depend on the additional add-on with timer functions, then yes, it opens an offer to buy and install it. I give the author 5 stars. And, depending on which option you choose, it DOES 'restart' the browser remembering which tabs were open a couple of ways. Thank you, Nacho.
(PS - There is also a secondary add-on which works with this one. I think it's $3.00 and gives you options to time restarts with other functions.)

Doesnt add a button really, adds a tab with a button on that page. Needs to be a button on the tool bar to be functional

Не работает. Удалите уже это отседа. Перезапуск браузера — фиктивный.

had to uninstall, because any benefit this plugin has is negated by constantly spamming the authors site on EVERY little update!

This doesn't restart the browser itself, but closes all tabs and opens them again

Everytime Firefox updates, this add-on loads some ridiculous page and also gives you a toast message near the taskbar asking for donations. Uninstall.

Не работает. Не только не перезапускает браузер, но еще и уничтожает сессию, сбрасывает открытые окна и вкладки. FF94

Its function was fine but it would open a new window with this its download page open, as a hint that I should make a contribution presumably, on start up and as a result my previous session would not open, requiring that I open my previous session from History, Recently Closed Windows. So I removed it.

This addon doesn't work properly - the tabs opened after restart are (very) different.
Also - and this is really bad - here is the list of permissions used. How can this be justified.

Access your data for all websites
Exchange messages with programs other than Firefox
Display notifications to you
Access browser tabs
Access browser activity during navigation

I don't know who Nacho Vázquez is, but judging by that list I don't trust him.
I'm about to uninstall, but I will repeat the tip given by mjjordan :
If you want a TRUE Firefox restart IN TWO CLICKS, do this:
1) Type about:restartrequired in your browser
2) Drag and drop that page to your toolbar
3) Click "Restart"

This addon does not restart the browser.