Could you clarify what you're looking for? Knowing the or the topic of the blog (e.g., software, music, or gaming) would help me track it down for you.
That sounds like a specific file name you'd find on a download site or in a forum. The query is a bit —are you looking for information on how to open/join multi-part RAR files, or are you trying to find a specific blog post that contains that link? caldo.part03.rar