-# If a line number is prefixed with "squash", "edit", or "reword", the
-# respective line's command will be replaced with the specified one.
+# "<cmd> <lineno>" -- add a line with the specified command
+# ("squash", "fixup", "edit", or "reword") and the SHA1 taken
+# from the specified line.
+#
+# "#" -- Add a comment line.
+#
+# ">" -- Add a blank line.