You can find "Open Source" versions of similar frameworks on the Roblox Library. Searching for "Robot 64 Movement Engine" often yields kits that replicate the portable feel of the game.
Instead of hunting for a dangerous "uncopylocked portable" file, consider these official alternatives: robot 64 uncopylocked portable
Stay safe, keep jumping, and always eat your ice cream before the whale does. You can find "Open Source" versions of similar