Does ESRI support GML?
Yes. Geography Markup Language is an OpenGIS Implementation Specification designed to transport and store geographic information. It is a profile (encoding) of XML (Extensible Markup Language). OGC Web Feature Services (WFS) for ArcIMS currently implement interfaces for data manipulation operations on GML features served on data stores that are accessible via the Internet. ESRI has created an Interoperability extension for ArcExplorer–Java Edition 4.0.1 to access OGC Web feature services as well as read GML files directly. ESRI is also building prototype ArcGIS implementations that utilize GML for accessing geographic features.