The meaning of color signs in Backports packages.

["Luca Renaud" <renaud.luca@gmail.com>]

Several packages (if not all) in backports.org when we search them in http://packages.debian.org/ appear with
the letters in red: backports(in red),is this a specific warning sign? Or just to remember that these packages
do not have security updates treated as the packages in stable?Examples:gnash,gnu-fdisk etc.
With gnash when we watch the list of backports for different architectures(amd64,i386,powerpc),

we saw them in different colors: amd64 yellow,i386 green,powerpc and others red,and it is more confusing.
I am talking about the page http://packages.debian.org/gnash and http://packages.debian.org/etch-backports/gnash.