@Sirlockinbottom A blueprint is something that gets added to an avatar upon upload.
Essentially, it's a signature that tells VRChat what upload of the avatar it is and makes it so when you update an avatar and upload it, it updates that instance of the avatar instead of uploading an entirely new version, because it knows it's the same upload.
It also links the avatar to your account so if you you were banned after uploading it, make a new account, and try to reupload the same avatar with the same blueprint then it will detect this and tie your new account to your banned account and ban the new account for evasion.
In essence, just detach the blueprint just in case.