I've been working on integration of ABRT with Project Atomic and, today, my work landed in Fedora 22 .
To enable abrt core_dump helper on Atomic hosts, it is necessary to install abrt-atomic package and enable abrt-coredump-helper service. After doing so core dump files will be stored in sub-directories of /var/tmp/abrt/.
You can find more technical details here:
Should I write a new proposal for the oversight repository or should I just open a new pull request for fedora-atomic repository?