`<script type="module">` results in `data:module;base64,...`

Input tags like `<script type="module" src="..."></script>` result in output tags like `<script crossorigin="" src="data:module;base64,..."></script>` which doesn't seem valid nor loads in Chrome.

I don't believe `module` is a valid MIME type, and if I edit the output file to use `text/javascript` instead, the file loads fine.