Open Firefox and press Alt + T keys to open the Tools menu, then select Add-ons. Make sure that the Add-ons tab is selected in the top right corner.
In the list of installed add-ons, find the "YouTube Downloader and Converter" add-on and click once on it. Then, check the dropdown menu or click the more options icon to see if a 'remove' option is available. If it is, click on it to uninstall the add-on. If not, proceed to the next step.
To manually uninstall the add-on, close Firefox and navigate to the profile directory of the Firefox installation. The path may vary, but it is usually:
~/.mozilla/firefox/your profile name/chrome.
Inside this directory, look for the folder with the same name as the add-on. The add-on might be stored under `"extensions" and may be present in the following format "youtube-downloader-converter@sidereel". Delete this folder.
Relaunch Firefox and check if the add-on is still installed by repeating the steps from step 1.
Start Firefox in Safe Mode by holding down the Shift key while double-clicking on the Firefox icon or by going to the Help menu and selecting Start in Safe Mode. While in Safe Mode, check if the add-on is still visible or not. If not, it might indicate that the add-on is causing the issue.
If the add-on is a developer extension and you are missing its 'remove' button, try setting your Firefox profile to its default settings. However, this may not be a viable solution.
If none of the above steps help, it might be best to contact the add-on's developer for direct assistance or guidance on how to uninstall their extension.
To remove the "youtube downloader and converter" add-on from Firefox without its 'remove' button, you must delete the related files manually in the Firefox installation directory and check for any signs of malware associated with the add-on.
