About the meaning of messages which is output by executing XPSImport command.
Lock Policy Store to prevent updating by AdminUI, smconsole...etc
Create objects mapping and establish connection with Policy Store
Read and load Policy Data (.xml)
Analyze Policy Data (.xml), if objects, values references and security data are correct or not
Validate Policy Data (.xml) in Policy Store
Save Policy Data (.xml) in Policy Store
Unlock Policy Store and cleanup finishing work