So an app has a Tab that is automatically there - I don't want it there... I could delete the "extratab" code but that could screw me over in the longrun. Where would I remove the tab this app created?
Bear in mind that if you ever update XenCarta, the tab will come back.
Another way (though slightly more convoluted) is to enable Debug mode.
You can then access the Development tab in the Admin CP. Then under Code Event Listeners > XenCarta you can disable the nav_tabs listener. This will keep it disabled, and shouldn't be reinstated after updates.