From my recent search, it's a selective video platform plug in. You can uninstall it with no worries. It's a type of Malware, not sure the origin for your case. But there's two ways about going through this.

1. (Windows: Start, Settings, Control Panel, Uninstall a Program) 2. Run a Malware scan (MalwareBytes (My suggestion)) NOTE: Any software for scanning is on your decision process.

Hopefully the first reply will take care of it, but just in case:

If this is showing up on the Add-ons page, did you see a Remove button?

You can view, disable, and often (but not always) remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. Then cast a critical eye over the list on the right side. Any extensions that Firefox installs on its own are hidden from this page, so everything listed here is your choice (and your responsibility) to manage.

If an extension does NOT have a Remove button, that indicates it was installed into a shared location. You may have the best luck removing it through an entry in the Windows Control Panel, Uninstall a Program, or you may need to hunt it down on disk. For hunting instructions, check out my next reply.

If there is neither a Remove button on the Add-ons page, nor a convenient uninstall option in the Windows Control Panel, here's one way to locate mystery extensions.

Open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter/Return

In the first table on the page, click the "Open Folder" / "Show in Finder" button. This should launch a new window listing your settings files.

Resize this window so you can see the Troubleshooting Information page behind it.

Scroll down and find extensions.json and click and drag it over to the Troubleshooting Information page, and drop it there.

Firefox should open the file in a structured viewer. You can choose different ways to look at the file, but the most efficient thing to do is use the search box in the upper right corner of the page to search for part of the name of the extension you want to locate. That should help you find the full details for it. Screenshot example attached.

In particular, the descriptor gives its location on disk. You may need to use the little triangles to expand the information and if the descriptor doesn't contain one of those words, you can make a note of the object number, then cancel the query and expand the list to that extension by hand.

(On Windows, the \ in folder paths is doubled in this file due to the way it is processed. When exploring your disk, read \\ as \. Not sure about Mac.)

Can you track it down?