Looks like we should be using https://schema.org/breadcrumb instead anyways. These attributes only exist for search engine robots anyways, I don't know why Firefox is complaining.
nginx problem NodeBB
hello! i'm noob NodeBB user i installed script correctly and was searching for decent NodeBB template but few days ago after php version update i got error like this http://www.asysteo.pl and i really dont have idea what happend. I checked all instalation readme files and I even installed NodeBB again still no success.