found the reason with curl:

curl -i thispersondoesnotexist.com

HTTP/1.1 301 Moved Permanently

Date: Wed, 01 Mar 2023 16:31:28 GMT

Transfer-Encoding: chunked

Connection: keep-alive

Cache-Control: max-age=3600

Expires: Wed, 01 Mar 2023 17:31:28 GMT

Location: https://stability.ai/