VRChat's Community Guidelines strictly prohibit reverse-engineering or using bots to gain unauthorized access to data. While downloading your own content is generally tolerated for recovery, "ripping" someone else's avatar is a bannable offense.
Using the in-game "Clone Avatar" button if the creator has enabled it. (Authorized). Avatar Ripping vrchat avatar id downloader link
: A specialized tool often used to browse or recover avatars. vrchat avatar id downloader link