+.It Va GraphDumpFile Li = Ar filename Bq experimental
+If this option is present,
+.Nm tinc
+will dump the current network graph to the file
+.Ar filename
+every minute, unless there were no changes to the graph.
+The file is in a format that can be read by graphviz tools.
+If
+.Ar filename
+starts with a pipe symbol |,
+then the rest of the filename is interpreted as a shell command
+that is executed, the graph is then sent to stdin.