Sync and safety:

Sync choice per device: Local (new default), Firefox Sync or GitHub Gist. Local and Gist keep bookmarks on the device only.
Gist Pull / Push / Sync now buttons, like git:
Push does nothing if the gist already matches.
Push is refused while the gist has changes this device hasn't pulled; "push anyway" overrides.
You see what will change and confirm before anything is deleted.
A status line says what's waiting to pull or push.
Automatic sync can be turned off.
Mass-deletion protection:
automatic sync pauses instead of deleting 10 or more bookmarks;
deleting all bookmarks, or 50 or more, means typing the number;
Import never deletes.
Automatic backups on each device (daily and before risky operations), with Restore in Settings and a warning when bookmarks suddenly shrink.
Import of a backup restores bookmarks that were deleted before, on every device.
Storage:

About twice the room in Firefox Sync (compact format). A video that got too big for Firefox Sync goes back to syncing once it fits.
Everyday use:

Rename (pencil) button in the full bookmark list.

Version 0.3.0

Now works on Firefox for Android
- On your phone, your bookmarks now appear below the video, with "+ Add here", a bookmark button in the player's top bar, and markers on the progress bar.
- Rename and delete buttons stay visible on touch screens.
- The toolbar popup fills the phone screen.

New: sync between your computer and phone with GitHub Gist (optional)
- Firefox Sync is still the default, but it only syncs between computers. Firefox does not sync extension data to Firefox for Android.
- To include your phone, open Settings > Sync on each device, choose GitHub Gist, and paste a GitHub token that has only the "gist" scope. The first device creates a secret gist in your GitHub account, and your other devices find it automatically.
- Bookmarks from all your devices are combined. Nothing added on one device is lost, the latest rename or star wins, and deleted bookmarks stay deleted.
- Sync runs a few seconds after each change, when Firefox starts, every 15 minutes, and when you open a YouTube video or the popup. Settings has a "Sync now" button and shows when the last sync happened.
- Your token is stored only on the device where you enter it. It is never synced or exported.
- The gist file uses the same format as Export, so you can also import it as a backup.

Privacy
- GitHub Gist sync is off unless you turn it on. When it is on, your bookmarks (video IDs, timestamps, titles and video names) are stored in a secret gist in your own GitHub account. Secret gists are unlisted, not private: anyone with the link can open them.

Fixes
- Opening a bookmark from the popup now reuses an open mobile YouTube tab.
- Video names are no longer briefly saved as "YouTube" while the mobile page is loading.

This update does not ask for any new permissions.

Smart bookmark titles: when a video has chapters, a new bookmark is pre-filled with the current chapter name instead of the generic "Bookmark". Videos without chapters still default to "Bookmark".
Quick per-video export: an Export button now sits next to ＋ Add here in the panel below the player. It downloads just that video's bookmarks (title included) and re-imports cleanly. Shown only when Individual video export is enabled in Settings and the video has bookmarks.

Fixed

Export all could produce a partial file on larger libraries — the download was cut short before the browser finished writing it. Exports are now complete. (Same fix applies to per-video export.)

Changes:
- Show only videos with saved bookmarks.
- Add individual deletion with confirmation.
- Add a Videos/Settings sidebar; Videos opens first.
- Add the sidebar icon and Settings version display.
- Support narrower windows.

0.2.0

• Bookmarks, favorites, and video titles now sync across devices via your Firefox Account (browser.storage.sync). Falls back safely to this-device-only storage if a bookmark ever can't fit in sync — you're notified on the Settings page, nothing is lost.
• Toolbar popup redesigned: icon-only header, a Bookmarks/Favorites toggle, and a search icon that expands into a filter box only when needed.
• New: star any bookmark to pin it to a Favorites view.
• New: video titles are captured automatically and shown next to your bookmarks (older bookmarks get their title filled in via YouTube's oEmbed lookup).
• Settings page redesigned to match the popup's dark theme, with a bigger bookmark list and clearer per-bookmark time badges.
• Existing local bookmarks migrate automatically and safely to the new sync-ready storage the first time you update.