I downloaded the latest footprints from kicad release from: Footprints (kicad.github.io) and pasted it in my local installation folder.
After opening kicad and loading the footprint library, I get the following message printed out for a few components “Unknown token “footprint” in input/source”.
Just to be clear:
I do not know if you installed libraries that are designed for KiCad-nightly V5.99.
It was just a guess that this could be a possible cause of your problems.
“Master” is the default branch and KiCad uses it for ongoing development, so it’s for the development version of KiCad. You can choose a tag for a specific version from the dropdown list instead of master (they are in the end of the list of branches).
On the other hand, you could install the libraries in the same way you installed the application. On Windows they are either bundled with the full installer or are a install time download option in the lite installer. On Linux they are distinct packages to be installed with the distro’s package manager.
If you decide to do this manually, you have to take care of certain things which otherwise are automatic and standard. As this thread shows.