Lua5.3.3r.dll -

The "r" in Lua5.3.3r.dll denotes a specific build of the Lua DLL, likely compiled with certain optimizations or modifications. This DLL contains the Lua runtime environment, which allows applications to execute Lua scripts and interact with the language's features.

lua53.dll is a generic name often used for Lua 5.3.x but without the patch version (3) or the “r” release flag. They are not interchangeable. An application hard-coded to load lua5.3.3r.dll will fail if only lua53.dll exists. lua5.3.3r.dll