sync: Drop Firefox-related entries
They used to be there for when we used to maintain PureBrowser, but since we're using Firefox these days they shouldn't be here anymore.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this page for instructions on how to get full permissions. Sorry for the inconvenience.
They used to be there for when we used to maintain PureBrowser, but since we're using Firefox these days they shouldn't be here anymore.