astro/.changeset/dirty-cooks-explode.md

@astrojs/mdx
major

Handles the breaking change in Astro where content pages (including .mdx pages located within src/pages/) no longer respond with charset=utf-8 in the Content-Type header.

For MDX pages without layouts, @astrojs/mdx will automatically add the <meta charset="utf-8"> tag to the page by default. This reduces the boilerplate needed to write with non-ASCII characters. If your MDX pages have a layout, the layout component should include the <meta charset="utf-8"> tag.

If you require charset=utf-8 to render your page correctly, make sure that your layout components have the <meta charset="utf-8"> tag added.