inoreader-open-in-background-tab.user.js

// ==UserScript==
// @name         Inoreader open in background tab
// @namespace    http://mono0x.net/
// @version      0.0.1
// @author       mono
// @match        https://www.inoreader.com/*
// @match        https://irodr.netlify.app/*
// @grant        GM_openInTab
// @run-at       document-end
// ==/UserScript==

(function() {
    'use strict';

    const w = unsafeWindow || window;

    const open = w.open;
    w.open = (url, name) => {
        if (url === undefined) {
            return open(url, name);
        }
        GM_openInTab(url, {
            active: false,
            insert: true,
            setParent: true,
        });
        return true;
    };
    document.addEventListener('click', (evt) => {
        if (evt.target.href && evt.target.target === '_blank') {
            evt.preventDefault();
            w.open(evt.target.href, '_blank');
        }
    }, false);
})();