diff --git a/sc2/doc/devel/aniformat b/sc2/doc/devel/aniformat
index 94448db38..fca075142 100644
--- a/sc2/doc/devel/aniformat
+++ b/sc2/doc/devel/aniformat
@@ -2,6 +2,7 @@ For *.ani, *.sml, *.med, *.big files, each line is in following format:
 
 filename transparent_color colormap_index hotspot_x hotspot_y
 
-Filename is string, all others are ints, -1 means value not used.
+Filename is string, all others are int.
+-1 for transparent_color or colormap_index means it isn't used.
 This information is parsed in libs/graphics/sdl/3do_getbody.c