chromium/content/browser/resources/indexed_db/transaction_table.html

<style>
  .transaction.started,
  .transaction.running,
  .transaction.committing {
    font-weight: bold;
  }

  .transaction-list {
    margin-inline-start: 10px;
    border-collapse: collapse;
  }

  .transaction-list th,
  .transaction-list td {
    padding: 2px 10px;
    min-width: 50px;
    max-width: 100px;
  }

  td.transaction-scope {
    min-width: 200px;
    max-width: 500px;
  }

  .transaction-list th {
    background-color: rgb(249, 249, 249);
    border: 1px solid rgb(156, 194, 239);
    font-weight: normal;
    text-align: start;
  }

  .transaction {
    background-color: rgb(235, 239, 249);
    border-bottom: 2px solid white;
  }

  .transaction.created {
    font-weight: italic;
  }

  .transaction.started .state {
    background-color: rgb(249, 249, 235);
  }

  .transaction.running .state {
    background-color: rgb(235, 249, 235);
  }

  .transaction.committing .state {
    background-color: rgb(235, 235, 249);
  }

  .transaction.blocked .state {
    background-color: rgb(249, 235, 235);
  }
  .state {
    text-align: end;
    cursor: pointer;
    white-space: nowrap;
  }
  .state:hover {
    position: relative
  }
  .state a {
    margin-left: 10px;
  }
  .timing-popover {
    visibility: hidden;
    position: absolute;
    top: 0px;
    left: 100%;
    border: 1px solid black;
    padding: 10px;
    font-weight: normal;
    background: white;
  }
  .state:hover .timing-popover {
    visibility: visible;
    text-align: start;
  }
  .state:hover .timing-popover ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
  }
</style>
<div id="transactions">
  <span>Transactions:</span>
  <table class="transaction-list">
    <thead>
      <tr>
        <th title="Transaction ID (unique within Process)">
          ID
        </th>
        <th title="Type of transaction">
          Mode
        </th>
        <th title="Names of object stores used by the transaction">
          Scope
        </th>
        <th title="Number of requests that have been executed">
          Completed Requests
        </th>
        <th title="Number of requests that have not yet been executed">
          Pending Requests
        </th>
        <th title="Time since transaction creation">
          Age (ms)
        </th>
        <th title="Time since transaction started">
          Runtime (ms)
        </th>
        <th title="State in the transaction queue">
          State
        </th>
      </tr>
    </thead>
    <tbody></tbody>
  </table>

  <template id="transaction-row">
    <tr class="transaction">
      <td class="tid"></td>
      <td class="mode"></td>
      <td class="scope"></td>
      <td class="requests-complete"></td>
      <td class="requests-pending"></td>
      <td class="age"></td>
      <td class="runtime"></td>
      <td class="state">
        <span class="text"></span>
        <a title="View previous states">⏱</a>
        <div class="timing-popover">
          <strong>Previous States:</strong>
          <ul></ul>
        </div>
      </td>
    </tr>
  </template>
</div>