.RBXL files are files that define a place within the game describing a playing field consisting of 3D models (.RBXM files). This may consist of items such as parts, tools, scripts, and teams.

ROBLOX is a massively multiplayer on line game designed for children ages 6 and up and allows players to design their own LEGO-like customized characters as creatively as possible and share their designs with the rest of the game's playing community.