Firefox browser extension that manages video playlists and tracks playback history.
Load via about:debugging → "Load Temporary Add-on" → select manifest.json.
Create an .xpi file (the extension package format — just a ZIP with a different extension). Make sure manifest.json and other top-level files are at the root of the archive, not inside a subdirectory:
zip -r playlist.xpi manifest.json background.js content_scripts/ icons/ popup/ shared/
Mozilla will sign your extension without publishing it publicly:
.xpi as "unlisted" (self-distribution, not public).xpi.xpi permanently on any standard Firefox — no dev mode neededThe extension never appears in the public store.
.xpi on Firefox Developer Edition or NightlyStandard Firefox release enforces signature checks and ignores the bypass preference. Firefox Developer Edition and Nightly have xpinstall.signatures.required set to false by default, so they accept unsigned .xpi files as permanent installs.
Drag-and-drop the .xpi into the browser, or go to about:addons → gear icon → "Install Add-on From File".