How to pre-install a .deb file into rootfs

I have a recipe (for kura) which uses a do_compile to run kura's build process, and this in itself generates a .deb (i.e. I'm not doing anything within the *recipe* to create the .deb - it's done for me by kura's build steps). I can copy the .deb to the target and use dpkg on there to install it.

However I'd like to have it 'pre-installed' into the rootfs instead. I've referred to tips such as
https://lists.yoctoproject.org/pipermail/yocto/2014-July/020583.html - but a couple of questions/issues:

1. What internal variables can I use - at this stage in the bitbake - to set '/path/to/' to point to the recipe's directory?

2. Even if I [temporarily] hard-code the full path to the .deb in the image recipe, the ROOTFS_POSTPROCESS_COMMAND 'dpkg' step is error-free but all I'm seeing in the rootfs is the .zip that the .deb contains i.e. it doesn't seem to be doing actual installation of the package? (I'm not too familiar with .deb's, so I'm not sure which part of its content actually triggers/defines the copying & installation of the enclosed files - I guess this doesn't get shown by a 'dpkg --contents'?)

It really would be best to stop Kura from writing debs and instead find the directory that Kura stages the deb in and copy that directly to ${D} in your do_install.

Ross