The most recent [packages](https://www.swift.org/install/linux/fedora/39/#versions) and [container images](https://hub.docker.com/_/swift) seem to be for Fedora 39, which is already EOL: https://docs.fedoraproject.org/en-US/releases/eol/. Fedora 40 and 41 are the currently supported releases. It looks like the CI knows about [Fedora 40](https://github.com/swiftlang/swift-docker/blob/f44060cdf224436060d2df98a5c3f63f2600de63/swift-ci/main/fedora/40/Dockerfile).