How does Strongarm decide which variables need to be included in a feature When you enable Strongarm on a site that is already using Features, do these two modules work together to determine which Strongarm variables need to be included in a Feature, or is there additional work that needs to be done to ensure that the correct Strongarm variables are included? 

If more work is needed, what needs to be done?
Strongarm provides a component to features where you can manually select the relevant variables to export with that feature.

Some variables may be included by default, e.g node_type variables when exporting a node type, others may need to be manually checked and exported with the feature module.