The file extension refers to a compressed archive created with 7-Zip . Based on your query, "05-08.7z" most likely refers to one of two specific technical packages: Shogi AI: Tanuki "Háo" Evaluation Function
It is a high-performance evaluation function often used in tournament-style Shogi engine builds. Retro Gaming: Super Bender Boot Disc 05-08.7z
やねうら王のビルド手順 · yaneurao/YaneuraOu Wiki - GitHub The file extension refers to a compressed archive
If you downloaded this file from an unknown source, it is highly recommended to before extraction, as compressed archives are often used to hide malicious scripts. 05-08.7z