chromium/chrome/browser/resources/new_tab_page_third_party/new_tab_page_third_party.html

<!doctype html>
<html dir="$i18n{textdirection}" lang="$i18n{language}"
    $i18n{hascustombackground} $i18n{isdark}>
  <head>
    <meta charset="utf-8">
    <title>$i18n{title}</title>
    <style>
      html {
        --ntp-focus-shadow-color: rgba(var(--google-blue-600-rgb), .4);
        --ntp-theme-text-color: var(--google-grey-800);
        background-attachment: fixed;
        background-color: $i18n{colorBackground};
        background-position: $i18n{backgroundPosition};
        background-repeat: $i18n{backgroundTiling};
        height: 100%;
        overflow: auto;
      }

      @media (prefers-color-scheme: dark) {
        html {
          --ntp-focus-shadow-color: rgba(var(--google-blue-300-rgb), .5);
          --ntp-theme-text-color: white;
        }
      }

      html[has-custom-background] {
        background-image: image-set(
            url(chrome://theme/IDR_THEME_NTP_BACKGROUND?$i18n{themeId}) 1x,
            url(chrome://theme/IDR_THEME_NTP_BACKGROUND@2x?$i18n{themeId}) 2x);
      }

      body {
        align-items: center;
        display: flex;
        height: 100vh;
        justify-content: center;
        margin: 0;
      }

      cr-most-visited {
        --most-visited-focus-shadow: 0 0 0 2px var(--ntp-focus-shadow-color);
        --most-visited-text-color: var(--ntp-theme-text-color);
        --most-visited-text-shadow: none;
      }

      html[has-custom-background] cr-most-visited {
        --most-visited-text-shadow: 0 0 16px rgba(0, 0, 0, .3);
      }
    </style>
  </head>
  <body>
    <script type="module" src="strings.m.js"></script>
    <cr-most-visited></cr-most-visited>
    <script type="module" src="new_tab_page_third_party.js"></script>
    <link rel="stylesheet" href="chrome://resources/css/text_defaults_md.css">
  </body>
</html>