The fontconfig source files currently live in:

/jdk/src/<os-api>/classes/sun/awt/fontconfigs/<os>.fontconfig.properties

except for windows, which is in:

/jdk/src/<os-api>/classes/sun/awt/windows/fontconfig.properties

These files are used as input to a build tool to create files in the lib output directory. Since they aren't normal properties files to be compiled, cleaned or copied to the classes dir, they should be moved to the make/data dir.