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.

Based on a search of available information, there are no widely known, public, or interesting stories specifically linked to a file named "Fsta.part2.rar".

If this is related to a specific game, a forum post, or an interesting piece of digital history, could you share ?