This was announced on the Clear Linux dev mailing list:
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We were planning a backend change to our infrastructure that hosts download.clearlinux.org content in AWS S3 for higher availability/scalability. After this change was made, we discovered an issue with downloading packages that have special characters in their name, for example, the ‘+’ sign. Package downloads fail with 404 file not found errors. This prevents users from being able to do mock builds and create their own mixes given they are using packages with special characters in their name.
We hope to have this issue resolved quickly and apologize for the inconvenience. In the meantime, a workaround is to change the package source URL from “cdn.download.clearlinux.org” to “download.clearlinux.org”. Once this is done, packages that have special characters in their name will download again.
If you are building packages:
Set up a custom mock configuration file by following the steps in this README: https://github.com/clearlinux/common#customizing-the-mock-config
In the newly-created conf file, change all instances of "cdn.download.clearlinux.org" to "download.clearlinux.org"
If you are mixing:
In the .yum-mix.conf file replace instances of "cdn.download.clearlinux.org" with "download.clearlinux.org" in the baseurl section of the clear repo. The .yum-mix.conf file is created in the mix workspace directory by the mixer init command.
We will keep this thread updated on our progress toward resolution.