This is not a Standalone Plugin!
It only runs with PlaceholderAPI
To install this expansion, go to the following path of you server directory and paste the downloaded jar there.
plugins/PlaceholderAPI/expansions
After that either restart your server or register it directly in an online server by executing "/papi register HexParserPAPI.jar".
Placeholder:
%#_<hexcode without the '#'>%
returns the parsed color.