Marlin is an optimized firmware for RepRap 3D printers based on the Arduino platform. Many commercial 3D printers come with Marlin installed. Check with your vendor if you need source code for your specific machine.
Since eab3a89a82258641919a2aa03bc4900bdb2b9e63 we got an error on compilation
In file included from sketch/src/lcd/lcdprint_u8g.cpp:26:0:
sketch/src/lcd/u8g_fontutf8.h:12:23: fatal error: clib/utf8.h: No such file or directory
#include "clib/utf8.h"
^
Hello
Since eab3a89a82258641919a2aa03bc4900bdb2b9e63 we got an error on compilation
it's on travis too https://travis-ci.org/MarlinFirmware/Marlin/builds/366418389#L614