.mp4 (MPEG-4 Part 14), a widely compatible container format for video and audio.
John Wick: Chapter 3 - Parabellum - Page 10 - www.makemkv.com 7995-BR720p-SUBS-JOHNWICK3.mp4
SUBS indicates that subtitles are either "hardcoded" into the video or "soft-coded" as an optional track within the file. Content Overview .mp4 (MPEG-4 Part 14)
The subtitle "Parabellum" comes from the Latin phrase Si vis pacem, para bellum , meaning " If you want peace, prepare for war ". Contextual Notes meaning " If you want peace