ref. https://qiita.com/ishiyama0530/items/8f8afc6c36ca8ea4df56

notranslate.js

// ==UserScript==
// @name         notranslate
// @namespace    https://gist.github.com/djeeno/50292ffaef9f6deb952a4aed8b625a67
// @version      0.1
// @description  notranslate
// @author       djeeno
// @match        *
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    if (location.hostname === 'github.com' || location.hostname === 'gist.github.com' || location.hostname === 'gitlab.com' || location.hostname == 'medium.com') {
        Array.prototype.forEach.call(document.getElementsByClassName('content'), x => x.classList.add('notranslate'))
        Array.prototype.forEach.call(document.getElementsByClassName('file'), x => x.classList.add('notranslate'))
        Array.prototype.forEach.call(document.getElementsByClassName('final-path'), x => x.classList.add('notranslate'))
        Array.prototype.forEach.call(document.getElementsByTagName('pre'), x => x.classList.add('notranslate'))
    }
    if (location.hostname === 'blog.discordapp.com') {
        Array.prototype.forEach.call(document.getElementsByTagName('iframe'), x => x.classList.add('notranslate'))
    }

})();