Answer
Three metadata synchronizers are provided with ArcCatalog and are on by default:
- FGDC CSDGM
- ISO Metadata
- Geography Network Synchronizer
The FGDC and ISO synchronizers write properties of the item to the appropriate elements for the metadata standard. The Geography Network Synchronizer writes properties for ArcIMS Image and Feature Services to the ESRI section in the metadata document; also, a default content type is written into both an FGDC and ISO element where it is found and used as the document is published to an ArcIMS Metadata Service.