I have installed an extension to toggle the top tab bar on/off in Mozilla based browsers, and now I can toggle it on/off in LibreWolf.
The add-on Toggle Native Tab Bar is found on Mozilla.org
In order to use it, it's necessary to create a /chrome/userChrome.css file in your profile folder and add a few simple lines to it. Easy to follow instructions found on their github page here:https://github.com/irvinm/Toggle-Native ... ve-tab-bar
Using this in conjuntion with Sidebery side tab bar toggle is a great way to manage screen real estate while browsing.
pictured here tiled in KLV-spectrwm with ranger file manager