What is the use of strings like "-*- Mode: Python -*-" found at the top of some python files?

Here are the top few lines (all comments) from a python application. What do开发者_开发问答 the first two comment lines indicate? Are they special markers for another app?

# -*- Mode: Python -*-

# vi:si:et:sw=4:sts=4:ts=4

#

# Istanbul - A desktop recorder

# Copyright (C) 2005 Zaheer Abbas Merali (zaheerabbas at merali dot org)

# Portions Copyright (C) 2004,2005 Fluendo, S.L. (www.fluendo.com).

# All rights reserved.

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The first line is an emacs thing (although it may also be a vi thing). It basically tells it that it should use python-mode to read the file. You'll usually see this if the file ends in an extension other than .py.

As mentioned, the second line deals with spacings.

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Its define tab size 4 spaces to text editors like vi