Request option to flag "page could not be found"-responses as bad links

Example: Gitlab reports bad links by returning the following ( it would be nice to have this reported as a bad link )
<!DOCTYPE html>
<html>
<head>
  <meta content="width=device-width, initial-scale=1, maximum-scale=1" name="viewport">
  <title>The page you're looking for could not be found (404)</title>
  <style>
    body {
      color: #666;
      text-align: center;
      font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
      margin: auto;
      font-size: 14px;
    }

    h1 {
      font-size: 56px;
      line-height: 100px;
      font-weight: 400;
      color: #456;
    }

    h2 {
      font-size: 24px;
      color: #666;
      line-height: 1.5em;
    }

    h3 {
      color: #456;
      font-size: 20px;
      font-weight: 400;
      line-height: 28px;
    }

    hr {
      max-width: 800px;
      margin: 18px auto;
      border: 0;
      border-top: 1px solid #EEE;
      border-bottom: 1px solid white;
    }

    img {
      max-width: 40vw;
      display: block;
      margin: 40px auto;
    }

    a {
      line-height: 100px;
      font-weight: 400;
      color: #4A8BEE;
      font-size: 18px;
      text-decoration: none;
    }

    .container {
      margin: auto 20px;
    }

    .go-back {
      display: none;
    }

  </style>
</head>

<body>
  <a href="/">
    <img src="data:image/svg+xml;base64,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"
       alt="GitLab Logo" />
  </a>
  <h1>
    404
  </h1>
  <div class="container">
    <h3>The page could not be found or you don't have permission to view it.</h3>
    <hr />
    <p>The resource that you are attempting to access does not exist or you don't have the necessary permissions to view it.</p>
    <p>Make sure the address is correct and that the page hasn't moved.</p>
    <p>Please contact your GitLab administrator if you think this is a mistake.</p>
    <a href="javascript:history.back()" class="js-go-back go-back">Go back</a>
  </div>
  <script>
    (function () {
      var goBack = document.querySelector('.js-go-back');

      if (history.length > 1) {
        goBack.style.display = 'inline';
      }
    })();
  </script>
</body>
</html>
scivision / linkchecker-markdown

Request option to flag "page could not be found"-responses as bad links #19
