To Uninstall your TubeSpanner browser extension first go to the Manage Extensions menu from the top-right corner of your Browsers menu bar:
Next you will need to open the options menu for your TubeSpanner extension and select Manage Extension from the following list of options (shown above).
Scroll to the bottom of the following page and you will be provided with the option to Remove Extension.
Confirm your extension removal and refresh your page to finish the process.