Uninstalling an Addon is easy, it's just opening the addon manager. The problem here is that I can't load an older version of the desktop build to be able to delete that addon. The newest version of Construct 3 disables it automatically, so I get the notification everytime I start the editor while not being able to fix the problem (it doesn't appear in the addon list).
Displaying the URL in the desktop build could indeed solve the problem.