How to disable animated favicons?

This is a known concern:

• https://bugzilla.mozilla.org/show_bug.cgi?id=111373

And has not been added as a feature in the 16 years since it was first asked.

You can use extensions and code to remove these:

• http://lifehacker.com/5036881/how-to-block-distracting-animated-favicons

However, as you specific ask for extension-free options, the answer is "No, you cannot stop animated favicons."

For those looking for Greasemonkey solution:

// ==UserScript==
// @name        garant.ru
// @namespace   garant
// @description удаление favicon
// @include     garant.ru/*
// @include     www.garant.ru/*
// @version     1
// @grant       none
// ==/UserScript==
a=$('link[href="/images/favicon.gif?1"]')
a.attr('href',"/images/favicon-16x16.png")

Main idea is to change animated favicon source from animated file to non-animated file.