The tag is present in Lintian version 2.104.234. That is the most recent version we know about.
The given runlevel was included in both the Default-Start and
Default-Stop keywords of the LSB keyword section of this
/etc/init.d script. Since it doesn't make sense to both start
and stop a service in the same runlevel, there is probably an error in
one or the other of these keywords.
Refer to https://wiki.debian.org/LSBInitScripts for details.