The switch to strict HTML compilation is just not cool, and actively prevents upgrading sites which need to deal with remote content that is not written in strict HTML.
I also wish there could be a general purpose content processing API so I can plug a different format than markdown (such as typst)
this terrified me lol I'm on 5.1.x on most of my sites
This does not affect remote content, only the content written in .astro files. If you have remote content you'd use something like `set:html`: https://docs.astro.build/en/reference/directives-reference/#...
See this example: https://stackblitz.com/edit/github-ug3paw61?file=src%2Fpages...