Open Script opens a standard file dialog for choosing an existing script. A new Scripting Editor window then displays the selected script.
For detailed information about the MAXScript utility, open the MAXScript Help, available from Help menu MAXScript Help.
These files are saved as text files, and you can open them using the Open Script command.
MAXScript file (.ms).
MacroScript file (.mcr). MacroScripts define action items managed by the Customize User Interface dialog.