=item C<AUG_TYPE_CHECK> = 4
-Typecheck lenses (can be expensive).
+Typecheck lenses.
+
+This option is only useful when debugging Augeas lenses. Use
+of this option may require additional memory for the libguestfs
+appliance. You may need to set the C<LIBGUESTFS_MEMSIZE>
+environment variable or call C<guestfs_set_memsize>.
=item C<AUG_NO_STDINC> = 8