In technical terms, a "Roblox Map Stealer" is a script, plugin, or executable software designed to bypass Roblox’s built-in asset protection. Its primary function is to download a complete copy of a Roblox game place (the .rbxl file) directly to the thief's hard drive.
Map stealers hook into the game engine to package these local files into a .rbxl file format. This allows the user to open the stolen map in Roblox Studio as if they were the original developer. The Technical Limitations Roblox Map Stealer