This simple addon list tabs vertically in the sidebar. It also includes a few common tab operations in the sidebar.

Add this to userChrome.css to remove the tab bar etc.

#main-window:not([extradragspace="true"]) #TabsToolbar > .toolbar-items {
opacity: 0;
pointer-events: none;
}
#main-window #TabsToolbar {
visibility: collapse !important;
}
#TabsToolbar[inFullscreen]{
display: none !important;
}
#sidebar-box #sidebar-header {
display: none !important;
}
#sidebar-box{
min-width: 54px !important;
max-width: 300px !important;
}

Install

• License: GNU General Public License v3.0 or later
• Weekly downloads: 5
• Average daily users: 6
• Rating: 3/5 of 1 ratings
• Created: 2022-11-24 08:19:03
• Last updated: 2023-08-10 03:40:26
• Homepage:
• Support site and email
• Orig: https://addons.mozilla.org/en-US/firefox/addon/tabsidebar/
• API: {c236f4e9-d031-419b-86c3-b83037cf6a02}