github/gitlab jetbrains nav (click on the "Raw" button to install)

git-jetbrains-nav.user.js

// ==UserScript==
// @name     github/gitlab jetbrains nav
// @author   Mira
// @version  1
// @grant GM.xmlHttpRequest
// @match    https://github.com/*
// @match    https://gitlab.com/*
// ==/UserScript==

/***********************************************************************
 *
 *  tested with the greasemonkey extension on firefox
 *  https://addons.mozilla.org/de/firefox/addon/greasemonkey/
 * 
 *  this needs the "IDE Remote Control" plugin in your jetbrains IDE
 *  https://plugins.jetbrains.com/plugin/19991-ide-remote-control
 *
 *  optionally add additional "// @match" lines with your own
 *  gitlab instance
 * 
 ***********************************************************************/

document.body.addEventListener("click",function(e) {
  var linum = e.target.closest("[data-line-number]");
  if (linum && e.altKey) {
		e.stopPropagation();
    e.preventDefault();
    var lineNumber = linum.getAttribute("data-line-number");
    var file = linum.closest(".file, details");
    var fileName = file.querySelector(".Link--primary").innerText;
    GM.xmlHttpRequest({
      method: 'GET',
      url: "http://localhost:63342/api/file/" + fileName + ":" + lineNumber,
      headers: {
        Origin: 'https://github.com'
      }
    });
  }

  var linum = e.target.closest("[data-linenumber]");
  if (linum && e.altKey) {
		e.stopPropagation();
    e.preventDefault();
    var lineNumber = linum.getAttribute("data-linenumber");
    var file = linum.closest(".file-holder");
    var fileName = file.querySelector(".file-title-name").innerText;
    GM.xmlHttpRequest({
      method: 'GET',
      url: "http://localhost:63342/api/file/" + fileName + ":" + lineNumber,
      headers: {
        Origin: 'https://github.com'
      }
    });
  }

},true);