"edns.dnsp.co" reports the EDNS(0) parameters that arrived with your query. EDNS(0) is the extension mechanism defined in RFC 6891 that lets DNS carry more than the 512 bytes the original protocol allowed, and it is how features like DNSSEC and client subnet are negotiated.
The interesting part is that these values describe the last machine in the chain, not you. If you query through your ISP's resolver, the payload size and cookie you see belong to that resolver. A very small UDP payload size suggests something in the path is being conservative about fragmentation; the absence of a DNS cookie (RFC 7873) means your resolver is not using the standard anti-spoofing mechanism.
A query sent without any EDNS at all is also worth noticing. It means you are talking to something quite old, or to software that has deliberately turned the extension off.
prompt> dig +short edns.dnsp.co TXT "udp_payload_size=4096" "edns_version=0" "dnssec_ok=no" "options=(none)" "padding_bytes=0" "dns_cookie=no"