Research institutions often use numbered archives to store large batches of measurement data, such as NASA's ICARTT format or genomic contig lists.

Below is a guide on what these files are and how to manage them. Understanding the RAR Format

Large files are sometimes split into several smaller parts. If "25436" was part of a set, you might also see files ending in .r00 , .r01 , etc.. How to Open and Extract "25436.rar"