diff --git a/src/scala/dof.scala b/src/scala/dof.scala
index 24610b3..4d35949 100644
--- a/src/scala/dof.scala
+++ b/src/scala/dof.scala
@@ -40,8 +40,8 @@ object DOF {
   val isabelle_version = "2022"
   val isabelle_url = "https://isabelle.in.tum.de/website-Isabelle2022"
 
+  // Isabelle/DOF version: "Unreleased" for development, semantic version for releases
   val version = "Unreleased"
-    // Isabelle/DOF version: "Unreleased" for development, semantic version for releases
 
   val session = "Isabelle_DOF"
 
@@ -56,8 +56,8 @@ object DOF {
   val latest_doi = "10.5281/zenodo.6810799"
   val generic_doi = "10.5281/zenodo.3370482"
 
+  // Isabelle/DOF source repository
   val url = "https://git.logicalhacking.com/Isabelle_DOF/Isabelle_DOF"
-    // Isabelle/DOF source repository
 
   // Isabelle/DOF release artifacts
   val artifact_dir = "releases/Isabelle_DOF/Isabelle_DOF"
diff --git a/src/scala/dof_document_build.scala b/src/scala/dof_document_build.scala
index 3275bb2..851480d 100644
--- a/src/scala/dof_document_build.scala
+++ b/src/scala/dof_document_build.scala
@@ -28,6 +28,8 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+/*** document build engine for Isabelle/DOF ***/
+
 package isabelle.dof
 
 import isabelle._
diff --git a/src/scala/dof_mkroot.scala b/src/scala/dof_mkroot.scala
index fc066d0..2b34fea 100644
--- a/src/scala/dof_mkroot.scala
+++ b/src/scala/dof_mkroot.scala
@@ -29,7 +29,7 @@
  */
 
 
-/*** Prepare session root directory for Isabelle/DOF ***/
+/*** prepare session root directory for Isabelle/DOF ***/
 
 package isabelle.dof
 
diff --git a/src/scala/dof_tools.scala b/src/scala/dof_tools.scala
index b298a73..e859f05 100644
--- a/src/scala/dof_tools.scala
+++ b/src/scala/dof_tools.scala
@@ -28,6 +28,8 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+
+/*** command-line tools for Isabelle/DOF ***/
  
 package isabelle.dof