yahoo_transit.user.js

// ==UserScript==
// @name         Yahoo Transit
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @match        https://transit.yahoo.co.jp/timetable/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=yahoo.co.jp
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    Array.from(document.querySelectorAll('a[href^="/station/"]')).forEach(x=>{
        const li = document.createElement('li')
        const a = document.createElement('a')
        const url = new URL(x.href)
        const {1:station} = url.pathname.match(/^\/station\/(\d+)/)
        a.href = `/timetable/${station}`
        a.textContent = '時刻表'
        li.appendChild(a)
        x.parentNode.parentNode.insertBefore(li, x.parentNode)
    })
})();