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Install the ZIP on Firefox

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Important: an unsigned ZIP is loaded as a temporary add-on and disappears when Firefox restarts. Permanent installation will require a Mozilla-signed release.

Download

1. Open Releases and select the latest version.
2. Under Assets, download yt-looper-firefox-vX.Y.Z.zip.
3. Optionally download SHA256SUMS and compare the SHA-256 before installing.
4. Extract the ZIP to a folder that will remain available for the session.

If no release is listed yet, the project has not published its first public package. Do not use the Chrome or Safari ZIP because each package contains a browser-specific manifest.

Load temporarily

1. Enter about:debugging#/runtime/this-firefox in the address bar.
2. Click Load Temporary Add-on….
3. Select manifest.json from the extracted folder.
4. Open a regular YouTube video and confirm that YT Looper appears.
5. If its icon is inside the extensions menu, pin it to the toolbar for quick library access.

Firefox keeps the add-on only until the next restart. To reload the same build during the session, return to about:debugging and click Reload.

Private windows

Firefox disables extensions in private browsing by default. If required, open about:addons, select YT Looper, and enable Run in Private Windows.

Verify the download

macOS or Linux:

shasum -a 256 yt-looper-firefox-vX.Y.Z.zip

Windows PowerShell:

Get-FileHash .\yt-looper-firefox-vX.Y.Z.zip -Algorithm SHA256

Compare the result with the matching line in SHA256SUMS.

Official reference

Mozilla documents this process in Your first extension.

If the widget does not appear, see Troubleshooting and privacy.