I was trying to make the “closed_on” property available to an external database through the CC Export Tool.
I generated the DET file (feature flag). The generated file references that property as
properties.closed_on. It didn’t work.
I found this page on the wiki that references the field as
date_closed. This version worked fine.
FYI, I am using a self hosted instance of CCHQ which latest deploy diff points to this commit (in case this has been fixed).