Vim is a highly configurable text editor built to make creating and changing any kind of text very efficient. It is included as "vi" with most UNIX systems and with Apple OS X.
Vim script files are stored as plain text, similarly to other code, and the filename extension is usually .vim. One notable exception to that is Vim's config file, .vimrc.
Vim's native terminal-based interface doesn't rely upon menus or fancy peripherals or even "extra" keys like Ctrl or Alt. Vim (mostly) uses keys common to any keyboard, regardless of language, layout, or device (and those that aren't common can be remapped pretty easily).