+(defvar notmuch-show-signature-regexp "\\(-- ?\\|_+\\)$"
+ "Pattern to match a line that separates content from signature.
+
+The regexp can (and should) include $ to match the end of the
+line, but should not include ^ to match the beginning of the
+line. This is because notmuch may have inserted additional space
+for indentation at the beginning of the line. But notmuch will
+move past the indentation when testing this pattern, (so that the
+pattern can still test against the entire line).")
+