Fuseki 3.13.0 GET vs HEAD

I would expect the GET /ds/ to return 200 OK with a full dataset (quad semantics). Which it does:

GET /ds/ HTTP/1.1
Host: localhost:3030
User-Agent: curl/7.47.0
Accept: /

HTTP/1.1 200 OK
Date: Wed, 11 Dec 2019 09:49:11 GMT
Fuseki-Request-ID: 6
Vary: Accept,Accept-Encoding,Accept-Charset
Content-Type: text/trig
Transfer-Encoding: chunked

In that case I think HEAD /ds/ should return the same status code and headers (minus the response body), but it doesn't:

HEAD /ds/ HTTP/1.1
Host: localhost:3030
User-Agent: curl/7.47.0
Accept: /HTTP/1.1 400 Neither default graph nor named graph specified
Date: Wed, 11 Dec 2019 09:42:49 GMT
Fuseki-Request-ID: 5
Vary: Accept,Accept-Encoding,Accept-Charset
Content-Type: text/plain;charset=utf-8
Cache-Control: must-revalidate,no-cache,no-store
Pragma: no-cache
Content-Length: 59