SF Bug #1008310, os.major() os.minor() example and description change. Will backport.

Doc/lib/libos.tex

@@ -843,12 +843,14 @@ defines the newly created device special file (probably using
 \end{funcdesc}
 
 \begin{funcdesc}{major}{device}
-Extracts a device major number from a raw device number.
+Extracts the device major number from a raw device number (usually
+the \member{st_dev} or \member{st_rdev} field from \ctype{stat}).
 \versionadded{2.3}
 \end{funcdesc}
 
 \begin{funcdesc}{minor}{device}
-Extracts a device minor number from a raw device number.
+Extracts the device minor number from a raw device number (usually
+the \member{st_dev} or \member{st_rdev} field from \ctype{stat}).
 \versionadded{2.3}
 \end{funcdesc}