binNMU safe and ${binary:Version} or ${source:Version}

[Daniel Leidert <daniel.leidert.spam@gmx.net>]

Hello,

I currently try to understand, what I need to do to make my packages
binNMU-safe (I package several libraries). For a package I want to put
into Debian soon, I'm now trying to make it binNMU-safe. But what's
behind this? I tried to find documentation that explains the phrase (I
understand, wthat an binNMU is, but not, what binNMU exactly means for a
package). But I didn't find anything. I e.g. saw the bug-report against
xchat. But I don't understand, when I should use ${binary:Version}
(gnome-vfs2) or ${source:Version} (suggested in the bug-report). So
where can I find documentation about this?

Regards, Daniel