I got this when visit https://mirrors.fedoraproject.org/mirrorlist?repo=fedora-38&arch=x86_64
# repo = fedora-38 arch = x86_64 Using ASN 9808 country = CN country = SG country = TH country = JP
http://mirrors.jlu.edu.cn/fedora/development/38/Everything/x86_64/os/
https://ftp.yz.yamagata-u.ac.jp/pub/linux/fedora-projects/fedora/linux/development/38/Everything/x86_64/os/
http://ftp.iij.ad.jp/pub/linux/Fedora/fedora/linux/development/38/Everything/x86_64/os/
http://ftp.riken.jp/Linux/fedora/development/38/Everything/x86_64/os/
https://download.nus.edu.sg/mirror/fedora/linux/development/38/Everything/x86_64/os/
http://mirror2.totbb.net/fedora/linux/development/38/Everything/x86_64/os/
I random pick a mirror and download /os/images/boot.iso
Boot this iso, the Installer shows it’s a image
same as the metalink https://mirrors.fedoraproject.org/metalink?repo=fedora-38&arch=x86_64
seem dnf use this metalink as fedora repo.
Maybe need some fix?