Purpose of apt_rpm module?

Hello,

Can someone enlighten me on the purpose of apt_rpm module?
It requires BOTH apt and rpm, what distro it’s for?

-don

ps. Also, I know (centos based) distros with just rpm, which is not
supported as there is no rpm module, only yum. This is strange overall.

its for using apt-rpm which is a utility that adds a 'apt like
wrapper' around rpm, this is targeted at rpm based distros.

http://apt-rpm.org/about.shtml