Since this topic originated in a discussion about QEmu, I should probably say something about that.
It looks like the QEMU page in the developer documentation needs another revision.
As far as I know, you need to download the latest working plain qemu-x86_64 amber-phone image. Unfortunately, Jenkins (the build server) only indicates success by showing a green icon next to the build in the list on the left of the page, so some colorblind users will have difficulty seeing the status. If you are using a system with a non-x86_64 architecture, you are out of luck.
Linking to the current build is awkward because there are lots of different types of build mixed together. The permalinks on the Image Build page don’t distinguish between them. Maybe I could put an indirect link in the documentation to a page that stays up-to-date with the latest QEmu image.