In the early 2000s and 2010s, numeric filenames were the standard for file-sharing forums and bulletin boards (BBS). These sites used automated scripts to rename uploads to prevent duplicate entries and to obscure the contents from early search engine crawlers. "23708.rar" is a remnant of this era of digital anonymity, where the user had to know exactly what the number corresponded to via a separate index or forum post. Conclusion
Unique identifiers used by security researchers to catalog specific virus samples. The Risk of the Unknown 23708.rar
Legacy hardware drivers for obscure components. In the early 2000s and 2010s, numeric filenames
Are you writing about conventions?