Im trying to create a file upload in admin so I can add the default frontmatter.yaml on each page (this way I wont forget). I have the code below but I get "Unsupported file type: yaml" when adding the file.
fields3:
custom_file:
type: file
ordering@: 9
label: Default FRONTMATTER
destination: 'self@'
multiple: true
limit: 0
filesize: 20
accept:
- .yaml
This is as per the example https://learn.getgrav.org/16/forms/blueprints/how-to-add-file-upload#accept. I suspect it is something to do with media.yaml but I cant seem to find the MIME type for YAML files that works. That shows error "incorrect MIME type" whatever I put in from the many on google.

