In the Ultra Librarian tool, I load that *.bxl file, select my CAD tool of choice (Eagle) and export it:
After exporting, a report is shown with the information where the files are stored (the duplicated folders are strange?) and instructions how to import it into Eagle:
Following these steps, I have now the footprint in Eagle :
Finally, I can get footprints from NXP for the Kinetis Devices. It requires downloading multiple files and a converter. But this is fine, as it offers flexible conversion to many different CAD and PCB Layout tools, including the popular Eagle and Altium.