This user script recovers pixiv trial unlinked history items for Tampermonkey.

Pixiv trial history recovery.js

// ==UserScript==
// @name         Pixiv trial history recovery
// @namespace    http://tampermonkey.net/
// @version      2023-12-24
// @description  Try to recover Pixiv trial unlinked history items.
// @author       aachyee
// @match        https://www.pixiv.net/history.php
// @icon         https://www.google.com/s2/favicons?sz=64&domain=pixiv.net
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
//    console.log('Pixiv trial history recovery script start.');
    // HTMLのbodyエレメントが閉じていないのでDOMContentLoadedは起きない
    window.addEventListener("load", (event) => { // load or DOMContentLoaded
        console.log('load!');
        const target = document.querySelector("div._history-items");
//        console.log( 'target: ', target );
        const observer = new MutationObserver((mutationsList, observer) => {
            mutationsList.forEach(mutation => {
//                console.log('DOM changed:', mutation);
                if (mutation.type === "childList") {
//                    console.log("A child node has been added or removed.");
                    mutation.addedNodes.forEach(node => {
//                      console.log(node, "has been added.");
//                      console.log(node.tagName, "has been added");
                        if (node.tagName === 'SPAN' && node.className === '_history-item trial') {
//                            console.log('background-image:', node.style.backgroundImage);
                            const m = node.style.backgroundImage.match(/\/([0-9]+)_/);
                            if (m[1]) {
                                const fragment = document.createDocumentFragment();
                                const anchor = document.createElement("a");
                                const div = document.createElement("div");
                                anchor.href = `/artworks/${m[1]}`;
                                anchor.target = "_blank";
                                anchor.className = "_history-item show-detail list-ite";
                                anchor.rel = "noreferrer";
                                anchor.style.backgroundImage = node.style.backgroundImage;
                                anchor.textContent = "";//改行(CR)を出力したい場合はinnerText
                                div.className = "status";
                                anchor.appendChild(div);
                                fragment.appendChild(anchor);
                                node.parentNode.insertBefore(anchor,node);
                                node.parentNode.removeChild(node);
                            }
                        }
                    });
                }
            });
        });
        observer.observe(target, {
          childList: true // , subtree: true, characterData: true, characterDataOldValue: true, attributeOldValue: true
        });
    });
//    console.log('Pixiv trial history recovery script running.');
})();