How to host raw geojson files on GitHub? [SOLVED]

How do I host raw geojson files on github like Metabase's US map:

Mine keep coming up blank in the Metabase URL upload preview pane. The field data is there, the geojsons are valid, but the polygons and areas don't show up visually.

Hi @mesquest
Sounds like the file are not valid. There's nothing special done about the two maps Metabase has on Github.
Try checking your files through

Thanks @flamber, the files had linestrings instead of polygons.