--- a/src/Pure/Tools/main.scala Sat Feb 27 11:51:39 2021 +0100
+++ b/src/Pure/Tools/main.scala Sat Feb 27 13:01:36 2021 +0100
@@ -35,11 +35,21 @@
val roots = Path.explode("$ISABELLE_HOME_USER/ROOTS")
if (!roots.is_file) File.write(roots, """# Additional session root directories
#
-# * each line contains one directory entry in Isabelle path notation
+# * each line contains one directory entry in Isabelle path notation, e.g.
+#
+# $ISABELLE_HOME/../AFP/thys
+#
+# for a copy of AFP put side-by-side to the Isabelle distribution
+#
+# * Isabelle/jEdit provides formal markup for C-hover-click and completion
+#
# * lines starting with "#" are stripped
-# * changes require application restart
+#
+# * changes require restart of the Isabelle application
#
#:mode=text:encoding=UTF-8:
+
+#$ISABELLE_HOME/../AFP/thys
""")
}