Archives with this specific naming structure generally contain one of three things:
Occasionally, these archives contain small "cracktro" files (programs with music and animation used by software crackers) or early indie game demos. The Risks: A Digital Archaeology Warning INDBOYZ001.rar
Providing more context about where you first heard of it (a specific forum, video, or site) can help narrow down the search! INDBOYZ001.rar
Old-school file transfer protocols where data is stored for decades. INDBOYZ001.rar