The procedure documented here is badly out of date:

https://www.debian.org/doc/manuals/developers-reference/ch05.en.html#s5.9.3

Among other things, it does not mention dummy packages and imposes
unnecessary load on FTP masters.

The procedure here seems to be a little more up to date:

https://wiki.debian.org/Renaming_a_Package

Maybe the two should be merged? At the very least, it should be
mentionned that leaf binary packages *do* need a dummy package
otherwise they will not be updated properly.

#486368 is similar, but since it's only asking for an example, i think
this is a different issue: the documentation there is not only
lacking, it's incorrect.

It should also be "Breaks" and not "Conflicts", apparently. But this
seriously needs to be reviewed...

a.