Emacs file variable

By Emacs file variable, we mean the boilerplate runes that appear near the beginning of some source code files, usually delimited by " ". For example:
 * 1) !/usr/bin/python
 * 2) -*- coding: utf-8 -*-

The variable definitions can help to (for example) interpret or display the files.

This syntax apparently originates from the Emacs text editor. Subsets and extensions of it have been borrowed by many other text editors, viewers, and other software.

Specifications

 * GNU Emacs Manual §48.2.4.1 Specifying File Variables
 * PEP 263 -- Defining Python Source Code Encodings