Comment # 2 on bug 1207224 from Lukas Ocilka

It can be reproduced with simple curl too

curl -vvv
https://download.opensuse.org/repositories/windows:/mingw:/win64/openSUSE_Leap_15.4/windows:mingw:win64.repo

> GET /repositories/windows:/mingw:/win64/openSUSE_Leap_15.4/windows:mingw:win64.repo HTTP/2
> Host: download.opensuse.org
> user-agent: curl/7.87.0
> accept: */*
> 
* [CONN-0-0][CF-SSL] TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* [CONN-0-0][CF-SSL] TLSv1.3 (IN), TLS handshake, Newsession Ticket (4):
* old SSL session ID is stale, removing
* HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1)
* Connection #0 to host download.opensuse.org left intact
curl: (92) HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1)

It's not related to the Installer, zypper or libzypp