How to completely remove Firefox Multi-Account Containers Extension?

[DonaldLuck117]

Before submitting a bug report

• I updated to the latest version of Multi-Account Container and tested if I can reproduce the issue
• I searched for existing reports to see if it hasn't already been reported

Step to reproduce

1. I disabled all the syncing options. No sign-ins. Never signed in
2. I hit the “Remove” button under “Manage Your Extensions” / Homepage
3. I restarted Firefox
4. “Open New Container Tab” in right-click context menu still works

Actual behavior

The Multi-Account Container Extension cannot be 100% completely removed / deleted / uninstalled

Expected behavior

Is there not a way to completely remove the extension? The context menu option “Open New Container Tab” still shows up. It still works which means it’s still running, even though I removed it from the extensions

Additional informations

1. Deleting the containers.json file in the profile folder did not help. It reappears when reopening Firefox

2. Changing the value to false for privacy.userContext.enabled, privacy.userContext.ui.enabled in about:config did not work. These values won’t stick

3. Opening the prefs.js file with notepad and removing these lines is only way to hide “Open New Container Tab”:

user_pref("privacy.userContext.enabled", true);
user_pref("privacy.userContext.ui.enabled", true);

However, I’d really like to remove the extension, not hide it. What’s the ID for this extension? Are there registries associated with it? I just want to completely get rid of it. That’s all I ask…

Provide a copy of Troubleshooting Information page (optional)

https://www.reddit.com/r/firefox/comments/1fcj6i5/how_to_remove_firefox_multiaccount_containers/