Only Kontakt Player libraries will appear in the Libraries tab.
To make a library an official Kontakt Player library, we have to pay a special fee to Native Instruments. For libraries like Realivox – The Ladies or Realivox Blue, we paid for this privilege, because since they’re more expensive libraries, that fee is a small percentage of our costs.
But with RealiBanjo/RealiWhistle/Acoustic Lite, that fee would make us have to almost double the price. So we offer these inexpensive libraries as “Kontakt” libraries, as opposed to “Kontakt Player” libraries. (Those names do make it confusing! If you’d like more info, we have a separate FAQ on the differences between Kontakt Player and the Full Version of Kontakt.)
So RealiBanjo/RealiWhistle/Acoustic Lite instruments are loaded using the “Files” button at the top of the Kontakt interface, or the “Files” tab in the sidebar browser, or using Quickload (the “Quick” button at the top of the interface. Quickload is very slick, by the way. Many people prefer it to the Libraries tab.