mj-button-href.mjml

<mjml>
  <mj-body>
    <mj-section>
      <mj-column>
        <mj-button href="https://crates.io/crates/mrml">
          Don't click me!
         </mj-button>
        <mj-button href="https://crates.io/crates/mrml" rel="testing" target="_self">
          Don't click me!
         </mj-button>
      </mj-column>
    </mj-section>
  </mj-body>
</mjml>