It's worth reminding people that Firefox extensions that are part of Mozilla's "recommended extensions" program have been manually vetted.

> Firefox is committed to helping protect you against third-party software that may inadvertently compromise your data – or worse – breach your privacy with malicious intent. Before an extension receives Recommended status, it undergoes rigorous technical review by staff security experts.

https://support.mozilla.org/en-US/kb/recommended-extensions-...

Updates must also be vetted before being made available.