A ch4 file extension is related to the Charisma and used for its presentation files.
CH4 file extension - Charisma presentation
What is ch4 file? How to open ch4 files?
File type specification:
The ch4 file extension is associated with the Charisma, a presentation software. The ch4 file stores presentation created in the Charisma.
The Charisma seems to be obsolete product without support from developer.