png_tRNS          124 contrib/libtests/pngunknown.c #define png_tRNS PNG_U32(116,  82,  78,  83)
png_tRNS          133 contrib/tools/pngfix.c #define png_tRNS PNG_U32(116,  82,  78,  83)
png_tRNS          776 pngpriv.h      #define png_tRNS PNG_U32(116,  82,  78,  83)