+TIDY = tidy -latin1 -q -modify -indent -wrap 120 --tidy-mark no --mute MISSING_ATTRIBUTE --mute TRIM_EMPTY_ELEMENT
+# -latin1
+# docbook output is ISO-8859-1 and tidy assumes ASCII
+# -q
+# suppress nonessential output
+# -modify
+# modify the original input file
+# --mute MISSING_ATTRIBUTE
+# don't show <img> lacks "alt" attribute
+# or <table> lacks "summary" attribute
+# --mute TRIM_EMPTY_ELEMENT
+# don't show trimming empty <p>
+#