chromium/components/metrics/debug/field_trials.html

<style>
  :host {
    --google-grey-100: rgb(241, 243, 244);
    --google-grey-900: rgb(var(--google-grey-900-rgb));
    --google-red-700: rgb(197, 34, 31);

    --shadow-color: rgba(0, 0, 0, 0.1);
    --input-background: var(--google-grey-100);
    --primary-color: var(--google-grey-900);
    --warning-color: var(--google-red-700);
  }

  .blurb-container {
    color: var(--primary-color);
    font-size: .875rem;
    line-height: 1.4;
    margin-bottom: 1rem;
  }

  .blurb-warning {
    color: var(--warning-color);
    text-transform: uppercase;
  }

  p {
    white-space: pre-wrap;
  }

  div:has(>#manual-enroll-input) {
    align-items: baseline;
    display: flex;
    flex-direction: row;
  }

  #manual-enroll-input,
  #filter {
    flex-grow: 2;
  }

  div:has(>#filter-status) {
    display: flex;
    flex-direction: row-reverse;
  }

  #manual-enroll-input {
    background: var(--input-background);
    padding: 12px;
  }

  #filter {
    background: var(--input-background) url(chrome://resources/images/icon_search.svg) no-repeat 8px 50%;
    padding: 12px 12px 12px 36px;
    width: 100%;
  }

  .override {
    flex-direction: column;
  }

  .trial-header {
    align-items: center;
    display: flex;
    font-weight: bold;
  }

  .expand-button {
    background: var(--input-background) url(chrome://resources/images/icon_expand_more.svg);
    height: 2em;
    width: 2em;
    margin-right: 1em;
  }

  .trial-row[data-expanded='true'] .expand-button {
    background: var(--input-background) url(chrome://resources/images/icon_expand_more.svg);
  }

  .trial-row:not([data-expanded='true']) .expand-button {
    background: var(--input-background) url(chrome://resources/images/icon_expand_less.svg);
  }

  #filter,
  #manual-enroll-input {
    border: 1px solid transparent;
    border-radius: 3px;
    box-sizing: border-box;
    color: inherit;
    font-size: .8125rem;
  }

  .trial-groups {
    background-color: lightgrey;
    border: 1px solid;
    margin-bottom: .5em;
  }

  .trial-groups :has(input[type=checkbox]:checked) {
    background-color: lightblue;
  }

  /* Hide trials if all experiments are filtered out. */
  .trial-row[data-search-result='no-match'] {
    display: none;
  }

  /* If a trial isn't expanded, hide groups not enrolled or overridden. */
  #field-trial-list:not([data-expand-all='true']) .trial-row:not([data-expanded='true'])
    .experiment-row:not([data-enrolled='1']):not(:has(input[type=checkbox]:checked)) {
    display: none;
  }

  .experiment-row {
    align-items: baseline;
    display: flex;
    padding-left: .5em;
  }

  .experiment-name {
    flex-grow: 2;
    max-width: calc(100% - 6em);
    overflow-wrap: break-word;
  }

  .experiment-row[data-enrolled] .experiment-name::after {
      content: ' (enrolled)';
      font-weight: bold;
  }

  .hidden {
    display: none;
  }

  .experiment-row:nth-child(odd) {
    background-color: #c0c0c0;
  }

  .experiment-row:nth-child(even) {
    background-color: #d0d0d0;
  }

  .experiment-row[data-search-result='match']:nth-child(odd) {
    background-color: rgb(176, 176, 0);
  }

  .experiment-row[data-search-result='match']:nth-child(even) {
    background-color: rgb(192, 192, 0);
  }

  .experiment-row:nth-child(odd)[data-enrolled],
  .experiment-row:nth-child(even)[data-enrolled] {
    background-color: rgb(170, 221, 170);
  }

  #needs-restart {
    display: none;
    background: white;
    bottom: 0;
    box-shadow: 0 -2px 2px 0 rgba(0, 0, 0, 0.1);
    box-sizing: border-box;
    left: 0;
    padding: 16px;
    position: fixed;
    width: 100%;
    z-index: 10;
  }

  :host([data-needs-restart='true']) #needs-restart {
    display: block;
  }

  :host([data-needs-restart='true']) #field-trial-list {
    padding-bottom: 6em;
  }
</style>
<div class="header-box">
  <form>
    <div>
      <input id="filter" placeholder="Search 'MyStudy.Group'" autocomplete="on" name="experiment-filter">
      <div>
        <span id="filter-status"></span>
      </div>
    </div>
  </form>
</div>
<h1>field-trial-internals</h1>
<div class="blurb-container">
  <span class="blurb-warning">Warning: Experimental features ahead!</span>
  <span>By enabling these features, you could lose browser data or
    compromise your security or privacy. Enabled features apply to all
    users of this browser.

    Changes here apply only after restart, and are reverted after 3 restarts. Visit this page again to re-apply.
  </span>
</div>
<div id="field-trial-list"></div>
<div id="needs-restart">
  <div class="flex-container">
    <div class="restart-notice">Your changes will take effect the next time you relaunch Chromium.</div>
    <div>
      <button id="restart-button" tabindex="-1">
        Relaunch
      </button>
    </div>
  </div>
</div>