Hello,
You can always make your own custom rule(s), read this https://github.com/MoscaDotTo/Winapp2/blob/master/README.md
i think your example is: (but im not sure if it works, you have test it yourself. PS: use at your own risk)
[Your Custom Skype rule*] LangSecRef=3022 Detect=HKCU\Software\Skype DetectFile=%ProgramFiles%\Skype For Salesforce Default=False FileKey1=%AppData%\Skype\*\media_messaging\media_cache_v3|*.* Have a nice day