+Each debhelper command will record when it's successfully run in
+F<debian/package.debhelper.log>. (Which B<dh_clean> deletes.) So B<dh> can tell
+which commands have already been run, for which packages, and skip running
+those commands again.
+
+Each time B<dh> is run, it examines the log, and finds the last logged command
+that is in the specified sequence. It then continues with the next command
+in the sequence. The B<--until>, B<--before>, B<--after>, and B<--remaining>
+options can override this behavior.
+
+A sequence can also run dependent targets in debian/rules. For
+example, the "binary" sequence runs the "install" target.
+
+B<dh> uses the B<DH_INTERNAL_OPTIONS> environment variable to pass information
+through to debhelper commands that are run inside override targets. The
+contents (and indeed, existence) of this environment variable, as the name
+might suggest, is subject to change at any time.
+
+Commands in the B<build-indep>, B<install-indep> and B<binary-indep>
+sequences are passed the B<-i> option to ensure they only work on
+architecture independent packages, and commands in the B<build-arch>,
+B<install-arch> and B<binary-arch> sequences are passed the B<-a>
+option to ensure they only work on architecture dependent packages.
+
+=head1 DEPRECATED OPTIONS
+
+The following options are deprecated. It's much
+better to use override targets instead.
+
+=over 4
+
+=item B<--until> I<cmd>
+
+Run commands in the sequence until and including I<cmd>, then stop.
+
+=item B<--before> I<cmd>
+
+Run commands in the sequence before I<cmd>, then stop.
+
+=item B<--after> I<cmd>
+
+Run commands in the sequence that come after I<cmd>.
+
+=item B<--remaining>
+
+Run all commands in the sequence that have yet to be run.
+
+=back
+
+In the above options, I<cmd> can be a full name of a debhelper command, or
+a substring. It'll first search for a command in the sequence exactly
+matching the name, to avoid any ambiguity. If there are multiple substring
+matches, the last one in the sequence will be used.