Fsta.part2.rar
It's likely an (like a ZIP or RAR) that needs its counterpart ("Fsta.part1.rar") and a program like WinRAR or 7-Zip to be opened.
File names like this, which are split archives (part 2 of a set), are common, but without context, it could be anything from a digital archive of a project, a fan-made file, or part of a larger file set on a storage site. Fsta.part2.rar
If this is related to a specific game, a forum post, or an interesting piece of digital history, could you share ? It's likely an (like a ZIP or RAR)