Source code and makefiles for XXICC code release 0.0k. You should be able to edit make, .h, and .c files using any text editor. .gal files may contain control characters that confuse your text editor, so you may need to use the XXICC Object Editor (XOE). .xoe files generally contain graphics and require XOE.
For more information on XXICC and GalaxC, see the 'blog post XXICC (21st Century Co-design) release 0.0k and XXICC's home page: xxicc.org.