The RedHat bugzilla instance that the Fedora community uses includes lots of helpful e-mail headers in its communications. These can be parsed by different e-mail clients such as Evolution to give us more information about a bug notification. People have mentioned these from time to time on the Fedora mailing lists. I wanted to configure Evolution to show them too, but I could neither find the mails on the mailing list nor a reference document in bugzilla's documentation. I saved one of my e-mails to mbox and got the list out that way. Here it is, in case you were looking too:

X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Classification: Fedora
X-Bugzilla-Product: Fedora
X-Bugzilla-Component: <usually a package name>
X-Bugzilla-Sub-Component:
X-Bugzilla-Version: <Fedora version>
X-Bugzilla-Keywords:
X-Bugzilla-Severity: unspecified
X-Bugzilla-Who: <some email>
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Priority: unspecified
X-Bugzilla-Assigned-To: <some email>
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
X-Bugzilla-Comment: public
X-Bugzilla-Reporter: <some email>

I've added a few comments to explain what the headers are. In Evolution, you'd go to Edit > Preferences > Mail Preferences > Headers and add the headers you want to see to the list there.

Cheers!

PS: If you do find a reference list someplace in the documentation, please do let me know.