I am trying to import KiCad to Altium for further analysis on my PCB design. However the issue I am having is that the file extension on KiCad has recently changed. It used to be .pro and .sch for the project and the schematic, however now it is .kicad_pro or .kicad_sch. Is there anyway to get it back to the original extensions?
In general no. v6 formats have new features and even if there were a translator, it might lose essential information. You should ask for an updated Altium importer. Obviously this is not the concern of the KiCad project.
Edit: My post can be ignored because I did not read op carefully [as per @eelik note below]
KiCad v6 does import altium sch and PCB files natively (file → import non KiCad file, in standalone sch editor or PCB editor respectively). v7RC has even improved altium importer. There is no need to play with KiCad v5 and external plugins - converters.