Use the Extensions pane of Safari preferences to manage extensions.
Off/On switch
To turn all extensions on or off, click the switch. For certain extensions, the change does not take effect until you navigate to a new page.
Extensions list
All your installed extensions are listed. If updates are available, an indicator appears at the bottom of the list.
Extension settings
To see if any settings are available for an extension, select the extension in the extensions list. Any available settings appear in the box on the right.
To uninstall an extension, click its Uninstall button.
Get Extensions
To view extensions available for Safari, click this button. A webpage opens providing a list of extensions, including descriptions and instructions for downloading and installing them.