Tab location
Does the latest version of Firefox allow you to have the tabs below the bookmarks. In the past, new versions place the tabs above and would not allow you to move them to the bottom. I have not updated many months, because I like the tabs on the bottom.
Todas as respostas (1)
Firefox 29 and later no longer have a built-in option to move the tab bar. In Firefox 29-56, add-ons could move the bar. In Firefox 57+, you need to use custom style rules in a userChrome.css file. Your rules will need updates from time to time to keep up with changes in the layout of the toolbar area, that's just the nature of the beast.
The attached screenshot shows the results of the rules here:
https://www.userchrome.org/what-is-userchrome-css.html#movetabbar