diff --git a/lib/spack/docs/packaging_guide.rst b/lib/spack/docs/packaging_guide.rst
index a859fceee72b56..ffaacfd8f13b34 100644
--- a/lib/spack/docs/packaging_guide.rst
+++ b/lib/spack/docs/packaging_guide.rst
@@ -4289,3 +4289,8 @@ Autotools-based packages would be easy (and should be done by a
 developer who actively uses Autotools).  Packages that use
 non-standard build systems can gain ``setup`` functionality by
 subclassing ``StagedPackage`` directly.
+
+.. Emacs local variables
+   Local Variables:
+   fill-column: 79
+   End: