cgeo/c-geo-opensource — comment on commit 221203e964b94c8b29b19142335d8ec5b8414601
File: tests/src/cgeo/geocaching/cgeoApplicationTest.java line 95
By SammysHP:

"GCGGG" is better because GC codes with four characters are hexadecimal, so 0-9A-F. "GC123456" is a valid GC code and may be used in the future.