Which one of email templates contains "email_posted_in"?

There is kind of blurb in each new comment email notification, started with "Posted in " and we'd like this to be removed.  I've searched across all theme templates,  email templates ( there are more than 30 of them so only templates containing "comment"  and / or "notification" ) and translations and the only possible match is in translations -> "email_posted_in" variable. I've asked official support  guys and got "this is out of support scope type of question". So I wonder if any hint could be found with the community help. Thanks in advance!