Bookmark the mangadex-display_in_library.min.js code.

display_in_library.ts

import * as mangadex from './shared';
import * as BM from '../shared';

mangadex.newBookmarklet(async () => {
	const authToken = mangadex.getAuthToken();
	const mangaStatuses: {
		statuses: Record<string, string>;
	} = await new Promise((resolve, reject) =>
		fetch('https://api.mangadex.org/manga/status', {
			headers: {
				Authorization: `${authToken.token_type} ${authToken.access_token}`,
			},
		})
			.then((rsp) => resolve(rsp.json()))
			.catch((e) => {
				alert('Failed to fetch manga statuses!');
				reject(e);
			}),
	);

	for (const mangaId in mangaStatuses.statuses) {
		const mangaStatus = mangaStatuses.statuses[mangaId];
		document
			.querySelectorAll('img[src^="https://mangadex.org/covers/"]')
			.forEach((img) => {
				const parentElement = img.parentElement?.parentElement;
				if (!parentElement) return;

				if (mangaId === img.getAttribute('src')?.split('/')[4]) {
					const statusElement = document.createElement('span');

					BM.setStyle(statusElement, {
						position: 'absolute',
						top: '0',
						right: '2%',
						padding: '0px 0.2rem 0.1rem',
						'border-bottom-right-radius': '0.25rem',
						'border-bottom-left-radius': '0.25rem',
						'font-weight': 'bold',
						color: 'rbg(var(--color))',
						'background-color': 'rgb(var(--md-primary))',
					});

					statusElement.textContent = mangaStatus
						.split('_')
						.map(
							(statusPart) => statusPart[0].toUpperCase() + statusPart.slice(1),
						)
						.join(' ');
					parentElement.appendChild(statusElement);
				}
			});
	}
});

mangadex-display_in_library.js

(() => {function newBookmarklet$1(websiteRegex, code) {
  if (!new RegExp(websiteRegex).test(window.location.hostname)) return alert('Bookmarklet executed on the wrong website!');
  code();
}
function getMatch(string, regex, index = 0) {
  const regexMatches = string.match(regex);
  if (regexMatches && regexMatches[index]) return regexMatches[index];
}
function parseStorage(key) {
  const value = localStorage.getItem(key);
  if (value) return JSON.parse(value);
}
function setStyle(element, styles) {
  for (const style in styles) element.style.setProperty(style, styles[style]);
}

const titleId = getMatch(window.location.pathname, /\/title\/+([-0-9a-f]{20,})/, 1) || getMatch(window.location.pathname, /\/title\/edit\/+([-0-9a-f]{20,})/, 1);
const newBookmarklet = (code, settings = {}) => {
  newBookmarklet$1('^mangadex.org|canary.mangadex.dev', () => {
    const isCreatePage = settings.createPage && /\/create\//.test(window.location.pathname);
    const noticePart = 'You can execute this bookmarklet only on ';
    if (settings.titlePage && !titleId && !isCreatePage) return alert(noticePart + 'a title page!');
    if (settings.editPage && !/\/edit\//.test(window.location.pathname) && !isCreatePage) return alert(noticePart + 'an edit page!');
    code();
  });
};
const getAuthToken = () => parseStorage('oidc.user:https://auth.mangadex.org/realms/mangadex:mangadex-frontend-stable') || parseStorage('oidc.user:https://auth.mangadex.org/realms/mangadex:mangadex-frontend-canary');

newBookmarklet(async () => {
  const authToken = getAuthToken();
  const mangaStatuses = await new Promise((resolve, reject) => fetch('https://api.mangadex.org/manga/status', {
    headers: {
      Authorization: `${authToken.token_type} ${authToken.access_token}`
    }
  }).then(rsp => resolve(rsp.json())).catch(e => {
    alert('Failed to fetch manga statuses!');
    reject(e);
  }));
  for (const mangaId in mangaStatuses.statuses) {
    const mangaStatus = mangaStatuses.statuses[mangaId];
    document.querySelectorAll('img[src^="https://mangadex.org/covers/"]').forEach(img => {
      var _img$parentElement, _img$getAttribute;
      const parentElement = (_img$parentElement = img.parentElement) === null || _img$parentElement === void 0 ? void 0 : _img$parentElement.parentElement;
      if (!parentElement) return;
      if (mangaId === ((_img$getAttribute = img.getAttribute('src')) === null || _img$getAttribute === void 0 ? void 0 : _img$getAttribute.split('/')[4])) {
        const statusElement = document.createElement('span');
        setStyle(statusElement, {
          position: 'absolute',
          top: '0',
          right: '2%',
          padding: '0px 0.2rem 0.1rem',
          'border-bottom-right-radius': '0.25rem',
          'border-bottom-left-radius': '0.25rem',
          'font-weight': 'bold',
          color: 'var(--color)',
          'background-color': 'var(--md-primary)'
        });
        statusElement.textContent = mangaStatus.split('_').map(statusPart => statusPart[0].toUpperCase() + statusPart.slice(1)).join(' ');
        parentElement.appendChild(statusElement);
      }
    });
  }
});})();

mangadex-display_in_library.min.js

javascript:(() => {function t(t,e,a=0){const o=t.match(e);if(o&&o[a])return o[a]}function e(t){const e=localStorage.getItem(t);if(e)return JSON.parse(e)}function a(t,e){for(const a in e)t.style.setProperty(a,e[a])}const o=t(window.location.pathname,/\/title\/+([-0-9a-f]{20,})/,1)||t(window.location.pathname,/\/title\/edit\/+([-0-9a-f]{20,})/,1);((t,e={})=>{(function(t,e){if(!new RegExp(t).test(window.location.hostname))return alert("Bookmarklet executed on the wrong website!");e()})("^mangadex.org|canary.mangadex.dev",(()=>{const a=e.createPage&&/\/create\//.test(window.location.pathname),n="You can execute this bookmarklet only on ";return!e.titlePage||o||a?!e.editPage||/\/edit\//.test(window.location.pathname)||a?void t():alert(n+"an edit page!"):alert(n+"a title page!")}))})((async()=>{const t=e("oidc.user:https://auth.mangadex.org/realms/mangadex:mangadex-frontend-stable")||e("oidc.user:https://auth.mangadex.org/realms/mangadex:mangadex-frontend-canary"),o=await new Promise(((e,a)=>fetch("https://api.mangadex.org/manga/status",{headers:{Authorization:`${t.token_type} ${t.access_token}`}}).then((t=>e(t.json()))).catch((t=>{alert("Failed to fetch manga statuses!"),a(t)}))));for(const t in o.statuses){const e=o.statuses[t];document.querySelectorAll('img[src^="https://mangadex.org/covers/"]').forEach((o=>{var n,r;const i=null===(n=o.parentElement)||void 0===n?void 0:n.parentElement;if(i&&t===(null===(r=o.getAttribute("src"))||void 0===r?void 0:r.split("/")[4])){const t=document.createElement("span");a(t,{position:"absolute",top:"0",right:"2%",padding:"0px 0.2rem 0.1rem","border-bottom-right-radius":"0.25rem","border-bottom-left-radius":"0.25rem","font-weight":"bold",color:"rbg(var(--color))","background-color":"rgb(var(--md-primary))"}),t.textContent=e.split("_").map((t=>t[0].toUpperCase()+t.slice(1))).join(" "),i.appendChild(t)}}))}}));})();