Ok, so I found the Directory, mentioned in the links. Talking about the Manual Method of Removing an App, from Firefox, in Linux. I did find the App, that I wanted to remove. I just moved the file, to a Backup Folder. In case I wanted to put it back. If doing this caused some kind of problem, in Firefox. Firefox showed now changes, in operation. And did not use any more or less resources. So, I put the App file back in the original folde. Just in case, it might cause something to go wrong, later on...
Firefox - uninstall app in Firefox
- uninstall app in firefox - Google Search
- Uninstall app from Firefox Marketplace with Iceweasel on Debian GNU/Linux | Firefox Support Forum | Mozilla Support
- uninstall marketplace app in Firefox desktop | Firefox Support Forum | Mozilla Support
- How to Delete Apps in Firefox | Chron.com
- How to remove Firefox Marketplace Apps on the desktop - gHacks Tech News
- Uninstall apps | Firefox OS Help