I'm not sure whether this belongs to infrastructure or rel-eng or some other team, so please pass this on if this isn't the right place.

Here are excerpts from two emails I got:

one:

From: buildsys@fedoraproject.org
To: matreshka-owner@fedoraproject.org
Subject: Broken dependencies: matreshka
Message-Id: <20170303132516.A98AB2857EB@branched-composer.phx2.fedoraproject.org>
Date: Fri,  3 Mar 2017 13:25:16 +0000 (UTC)
matreshka has broken dependencies in the rawhide tree:
On aarch64:
    matreshka-amf-utp-0.7.0-5.fc24.aarch64 requires libgnarl-6.so()(64bit)

two:

From: buildsys@fedoraproject.org
To: matreshka-owner@fedoraproject.org
Subject: Broken dependencies: matreshka
Message-Id: <20170303135349.8028320930@rawhide-composer.phx2.fedoraproject.org>
Date: Fri,  3 Mar 2017 13:53:49 +0000 (UTC)
matreshka has broken dependencies in the rawhide tree:
On aarch64:
    matreshka-amf-utp-0.7.0-5.fc24.aarch64 requires libgnarl-6.so()(64bit)

Seeing these together, so close in time, and able to compare the complete email headers, I can see the difference in the hostname of the sending computer, and conclude that one of them probably pertains to Rawhide and the other to Branched. When most header fields are hidden they're completely indistinguishable except for the timestamp.

When one receives only one or the other of these, and one isn't familiar with Fedora's server infrastructure, then a hostname hidden in the header fields is not sufficient indication of which branch the dependency problem is in. Those emails that pertain to Branched really must start mentioning "branched" or "f26" instead of "the rawhide tree".