I used this before the firefox API changes hamstrung it. The manual specification of the prefix is a reasonable workaround (since the API prevents the extension from reading the profile name). But now the profile string is showing up on every tab. It used to be that you could configure where it appeared (e.g., window title, context menu). Having it on every tab obscures the other content of the tab label (which is more important to me). If you can't support putting the profile prefix in those other locations anymore (due to API changes), maybe you could have an option to append to the tab label instead of prepending.