I sent an e-mail reply to https://pagure.io/fedora-infrastructure/issue/7273 today, and I noticed that it inserted an = symbol in the middle of a link I had included. Due to #3794 I will attach a screenshot in a comment below, but essentially it turned this:

https://fedora-infra-docs.readthedocs.io/en/latest/sysadmin-guide/sops/infra-repo.html

into this:

https://fedora-infra-docs.readthedocs.io/en/latest/sysadmin-guide/sops/infr=
a-repo.html

It seems that Pagure does not properly handle Quoted-Printable Content-Transfer-Encoding, specifically Rule #5:

The Quoted-Printable encoding REQUIRES that encoded lines be no more than 76
characters long. If longer lines are to be encoded with the Quoted-Printable encoding, 'soft'
line breaks must be used. An equal sign as the last character on a encoded line indicates
such a non-significant ('soft') line break in the encoded text.

Here is the relevant snippet of the raw e-mail that I sent to Pagure:

--=-ZAerKLEZX+wskEc3SXlk
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
On Tue, 2018-10-02 at 18:21 +0000, Kevin Fenzi wrote:
> I guess we could just try and remember anytime we move a package from
> the staging tag to prod, we also untag all the old builds of that
> same package.=20
>=20
> Thoughts?
If we decide to go that route, we should document it at
https://fedora-infra-docs.readthedocs.io/en/latest/sysadmin-guide/sops/infr=
a-repo.html
--=-ZAerKLEZX+wskEc3SXlk