Presently, there is no way to figure out from which site a particular
signal is coming from via the Unused signals report.For example:
c_article_title=top news doesn't tell us which site triggered this.So,
if there are 5 sites, we need to setup 5 traits and then wait to see
which one populates and then delete the rest which is a very inefficient
option. Manual lookup is not feasible in case of publishers with
multiple sites and while creating traits in bulk.