There is checked-in code for AtteanX::Store::DBI, but it's just a copy of the Memory store. I suspect this was accidentally checked in during some exploratory work on porting RDF::Trine's DBI code to Attean. That was never meant to happen, and it should be removed. Ideally it would be replaced in the future with a true DBI store (either ported from Trine or developed new).
There is checked-in code for AtteanX::Store::DBI, but it's just a copy of the Memory store. I suspect this was accidentally checked in during some exploratory work on porting RDF::Trine's DBI code to Attean. That was never meant to happen, and it should be removed. Ideally it would be replaced in the future with a true DBI store (either ported from Trine or developed new).