HoMM3 HD is a mod (add-on) for the game Heroes of Might and Magic 3.

There are no scripts there. It's just a regular text file. Open it with Notepad (or any text editor), ...
rebellious, what's that cool editor in the picture?

But the conversation was actually about violins :D
Any editor won't do. Notepad or something similar without text formatting. Or the TextEdit.exe editor, an old special Heroes text editor (everyone knows it). By the way, it has a very informative help section.