A modified version of chrome-one-tab to be compatible with firefox web extensions' new standards
This version works well with firefox version 75.0b3 except for one problem, the "restore all" button is not working if you choosed to restore tabs to a new window. Instead you can temporarily fix this by setting "restore all" button to restore tabs to the same winodw inside the "Options" page. Sadly there is no way for me to fix this as the js code is minimized, so lets go with this solution until the author fixes it.
you can find on mozilla.org through this link : https://addons.mozilla.org/en-US/firefox/addon/firefoxquantum-onetab/