Facebook Essentials (malware) has been blocked for your protection.

Why was it blocked?
This extension is malicious and is installed under false pretenses.
Who is affected?
All Firefox users who have installed this extension.
What does this mean?

The problematic add-on or plugin will be automatically disabled and no longer usable.

When Mozilla becomes aware of add-ons, plugins, or other third-party software that seriously compromises Firefox security, stability, or performance and meets certain criteria, the software may be blocked from general use. For more information, please read this support article.