Unsigned extensions in Waterfox

Waterfox can install unsigned extensions, including supported legacy add-ons. An unsigned extension has no Mozilla signing verification, so Waterfox may show a warning that it cannot be verified during installation or in the Add-ons Manager.

A verification warning tells you about the package’s signing status. It does not establish whether its author is trustworthy or whether its code is safe. Signing also does not mean that Mozilla staff regularly review an extension; add-on badges describe its review or recommendation status.

Before installing

Get the extension from its author’s official website or repository. Check that the author supports your Waterfox version, and review the permissions in the installation prompt. Extensions can access or change information according to those permissions.

For an extension downloaded as an .xpi file:

1. Open about:addons.
2. Open the tools menu and choose Install Add-on From File….
3. Select the file and review the installation prompt.
4. Confirm only if you trust the source and accept the requested access.

Restart Waterfox if requested. You can disable or remove the extension from Extensions in the Add-ons Manager.

If installation fails

A signing warning and an installation failure are separate conditions. An extension can fail because it is incompatible, damaged, or blocked. Record the exact error and check for an updated package from the author.

Waterfox retains protections against hard-blocked add-ons. An unsigned package’s support does not grant it an exception from those protections.

See Manage extensions and themes in Waterfox for general controls, and Extensions installed outside the add-on store for guidance on direct downloads and updates.