Files with rok suffix appear to be old update / firmware files for devices or programs produced by Roku company.
ROK file extension - Roku update file
What is rok file? How to open rok files?
File type specification:
File extension rok seems to be mainly related to a special update format used by Roku, an American manufacturer of home digital media products.
A .rok file appears to be a some sort of update file, possibly for firmware in certain Roku devices.