Document minor_version

Author: michaelni

ffv1.lyx

@@ -5641,6 +5641,13 @@ version 0, 1 or 3.
  Version 3 is still work in progress.
 \end_layout
 
+\begin_layout Labeling
+\labelwidthstring 12345678901234567890
+minor_version For version 3, minor_version is 2, minor versions prior to
+ this represent pre standard variants that should not exist in the wild.
+ Decoders must not reject a file due to an unknown minor_version.
+\end_layout
+
 \begin_layout Labeling
 \labelwidthstring 12345678901234567890
 \noindent