Tab01 by ntrezowan

Tab01 is a tab dependency tracker for Firefox. It answers a simple question Firefox ignores: where did this tab come from?

When you open a link in a new tab, Firefox forgets the connection immediately. Tab01 doesn't. It tracks parent-child relationships between tabs and shows them as a collapsible tree in the sidebar.

How it works

• Open the sidebar with the toolbar icon or press Ctrl+Shift+E (Cmd+Shift+E on Mac)
• Every tab you open is automatically tracked — no manual action needed
• If you open tab B from tab A, then open tabs C and D from tab B, you'll see the full tree: A → B → C, D
• Click any tab in the tree to switch to it
• Right-click for options: close the entire branch, close children only, or detach a tab from its parent

Features

• Automatic tree tracking — parent-child relationships are captured on every tab creation
• Collapsible tree view — expand and collapse branches in the sidebar
• Branch operations — close an entire branch (parent + all descendants) with one click
• Close children only — keep the parent, kill everything spawned from it
• Detach tabs — break a tab free from its parent to make it a root
• Search — filter the tree by tab title or URL. Press / to focus search
• Child count badges — see how many descendants each tab has spawned
• Active tab highlight — your current tab is always highlighted in the tree
• Right-click context menu — also available on tabs in the tab bar via Firefox's context menu
• Light and dark theme — follows your system preference
• Keyboard shortcut — Ctrl+Shift+E / Cmd+Shift+E to toggle the sidebar

Permissions explained

• tabs — needed to read tab URLs, titles, and opener relationships for building the tree
• storage — needed for future persistence features
• menus — needed to add "Close branch" and "Close children" to the tab context menu

No data is collected or sent anywhere. Everything stays on your machine.