ATW10MVTVFTV stands for "All Too Well 10 Minute Version Taylor's Version From The Vault." This is a reference to a new version of Taylor Swift's popular song "All Too Well" which was released in November 2021 on her album "Red (Taylor's Version)." The new version, referred to as the "10 minute version", features additional lyrics and explores the emotions and events of the relationship in more detail. The "From The Vault" part of the acronym refers to the fact that the song was recorded years ago and was previously unreleased.