Web Application Manifest MIME type

The application manifest MIME type is application/manifest+json .

If the protocol over which the manifest is transferred supports the [MIME-TYPES] specification (e.g. HTTP), it is RECOMMENDED that the manifest be labeled with the application manifest MIME type.

From the Web Application Manifest specification (W3C Editor’s Draft 09 March 2021).

The Content-Type header for files with the .webmanifest extension should be application/manifest+json instead of application/octet-stream. Read the specification for more information.

You can choose to switch to .json file or add a custom header: Custom headers | Netlify Docs.

I have added a custom header as a temporary workaround.

[[headers]]
  for = "/*.webmanifest"
  [headers.values]
    Content-Type = "application/manifest+json"

Hey there, @PizzaFox :wave:

Thank you so much for bringing this to our attention, and for sharing your workaround. I wanted to let you know that we are taking this suggestion to one of our teams for discussion. We will follow up on this thread if we have more information!