This is a GCC2/GCM2 unit made by AEG, a nifty device used in LCD passenger information displays at train stations to allow for colored line numbers on an otherwise monochrome display. It consists of a GCM2 (probably means "Geavision Color Module") board, which can be seen here - containing lots of THT LEDs in red, green, and blue colors, as well as fans to cool them. (fancy "extra quiet" ones funnily enough, as if that would matter) Underneath it is the GCC2 board ("Geavision Color Controller").