diff --git a/doc/guix.texi b/doc/guix.texi
index 7c02e2d392..3ed71424fa 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -5620,6 +5620,12 @@ The modules must be @b{underneath} the specified directory, as the
 defined as @code{(define-module (gnu packages fun))} must be located at
 @code{base/gnu/packages/fun.scm}.
 
+Doing this allows for only parts of a repository to be used as a
+channel, as Guix expects valid Guile modules when pulling.  For
+instance, @command{guix deploy} machine configuration files are not
+valid Guile modules, and treating them as such would make @command{guix
+pull} fail.
+
 @node Declaring Channel Dependencies
 @section Declaring Channel Dependencies