It also works quite well with the browser save feature. Curl and wget will also save to a nice name by default. It may be nice if content-type tracking was univ

It also works quite well with the browser save feature. Curl and wget will also save to a nice name by default. It may be nice if content-type tracking was universal but unfortunately file-extensions are probably the most robust way of tagging some data with a type (other than magic bytes). You can save that JSON, email it, archive it, upload it to a fileserver, someone downloads it again, decompresses it and uploads it in an HTTP form and the result will probably still be identified as JSON and highlighted by default in your editor.