The tag is present in Lintian version 2.104.244. That is the most recent version we know about.
The Debian diff or native package contains a file that looks like a
Subversion conflict file. These are generated by Subversion when a
conflict was detected while merging local changes with updates from a
source repository. Use
svn resolved to remove them and clear
the Subversion conflict state after you have resolved the conflict.