diff --git a/docs/doc-tex.txt b/docs/doc-tex.txt
index cbb09c4..e52a878 100644
--- a/docs/doc-tex.txt
+++ b/docs/doc-tex.txt
@@ -2,6 +2,10 @@
 devil1tex.h / devil1tex.c
     Handles texture packages.
 
+File Format
+    Texture packags can be identified with a string "\0 2 3 T" as a starting 
+    tag.
+
 Functions
     All functions are static but exposed by a function pointer in a constant
     struct called DEVIL1TEX. For example, clients call functions using