This is how I'm trying it on the test board by editing the field in the config table, but I'm not sure this is safe to do?
Sorry, I was editing while you were posting.
ETA: That doesn't work, it shows html in the tab, wasn't a good idea.
ETA2: If I hardcode it into overall header it displays smaller and does not show html in the tab. It would be OK this way as long as I'm not missing something.