Issue Description
There’s no description of how the engine determines what the value of this property should be. It can be set by the developer in Studio through the properties pane but otherwise it’s read only and not even the command bar is allowed to set this property.
A lot of developers create custom accessories so it’d likewise be informative to know how this is set internally. This would especially help when trying to write code that only acts on certain accessory types without needing to look for attachments and read their names off (GetAccessories → AccessoryType → execute code on accessory).
At the moment this property only gets set when the accessory is attached to a character through the spawning process or Humanoid:ApplyDescription() (which is mentioned on the linked URL). The accessory type will be the type which is on the web page for the accessory e.g the type for this accessory is Face: BubbleGum Candy (1.0) - Roblox. We will have a look into whether it’s appropriate to allow getting and setting of this property through Lua, but as you said it is not available at this time