User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:53.0) Gecko/20100101 Firefox/53.0 Build ID: 20170112030301 Steps to reproduce: I'm the maintainer of an Arch Linux AUR package for Firefox Nightly. The package script is designed to retrieve the binary, the build info file (to retrieve the build number) and the checksums file from https://ftp.mozilla.org/pub/firefox/nightly/latest-mozilla-central/ for the latest available nightly. Actual results: Since about 25 Jan 2017, but possibly a bit earlier, the checksums file is not present on the server for Linux i686 and x86_64 builds of Nightly 54. It is present for Nightly 53. It is also present for Mac and Windows builds of Nightly 54. The missing checksums file was causing my AUR package to fail. Expected results: The checksums file should be present alongside Nightly 54 for Linux builds. The AUR package has now been updated to NOT check integrity of downloaded files. Obviously this is a bad workaround, so I'll await news on this bug to restore integrity checking.