https://www.facebook.com/business/he...60266880806087
"Global Pages let your business provide localised versions of content for your customers all over the world with one universal brand name and the same vanity URL for each Page. You can also share total fan count and global insights across your entire fan base.
With Global Pages, you can post content that's meaningful for an audience in one location, and share different content that's just as relevant for an audience in another location. For example, you can share seasonal sales in one location, while reporting shop closures for a holiday in another location."
In short, they post on the @FinalFantasyXIV page in English, and Facebook redirects any users whose primary language is set to Italian to a @FinalFantasyXIV.IT subpage that auto-translates it to Italian.
So it is auto-translated by Facebook based on your Facebook settings (primary language). It will also do things like change times to your local time based on timezone. This is not controlled by your browser settings or any plug ins on your end, nor is it handled by SE themselves: it is 100% on Facebook's side.