As far as I understand it, ‘funckychicken’[.properties] is the name of your plugin, that’s used in the build script apply statement, apply plugin: ‘funkychicken’
com.build.WierdoPlugin is the class implementing the Plugin interface
This caveat caught me at first as well. I agree it’s in the User Guide, which I read, but it took many, many forum and blog reads before I finally connected all the dots.