Sounds like you mean the <title> tag. If so, this is still in the core unfortunately... in qa-includes/qa-page.php, line 628. You should have access to the $qa_request variable to check which page you are on.
What you can do for now if you need to modify the core is mark it with a special comment, e.g. I use double star and my initials: /** SV: [description] */
Then when an upgrade comes, back up the old core, upgrade to the new core, then search all the files in your backup for the special comment, i.e. /** SV in my case. Copy the modifications into the new core. A little bit messy but the easiest solution I've found.
But hopefully all output will move into qa_theme_base next time, so we don't need any of these hacks!