✅ Where does the extra linebreak come from (StringBuilder)?

            stringBuilder.AppendLine("\t<tr>"); // StringBuilder 

            foreach (string cell in cells)
            {
                stringBuilder
                    .Append("\t\t<td>")
                    .Append(cell)
                    .AppendLine("</td>");
            }

            stringBuilder.AppendLine("\t</tr>");

      <tr>
          <td>String</td>
          <td>name</td>
          <td></td>
          <td></td>
      </tr>

      <tr>

          <td>String</td>

          <td>name</td>

          <td></td>

          <td></td>

      </tr>