Do you mean FB vs FF as in fastbuds?
https://2fast4buds.com/feminized-seeds
they have their strains listed on the site at this link here, they also have FF fastflowering strains a hybrid of auto and photo and then they have Fem Photo, no auto in the mix.
growdiaries.com/seedbank/fastbuds/strains
They are at the very bottom and have no reviews yet. I have heard about other photoperiod testers they released and they all seemed to do ok. None of them made it to the official launch of the current photoperiods though. I would assume they only put forward the ones that are good. Its still weed and will likely do just fine. Its not like FastBuds is expert seed or garden of green and slap a label on any garbage seeds they find and releases 100's a year. I would trust their Fem Photoperiods over a less knowen seedbank like Ministry of cannabis or art genteix who hosted a few contests here.