Geography Markup Language, GML

Anybody knows anything about this format? In my country we have a custom national format for mapping data, but this is now being phased out, because GML is an international standard.

However, I have trouble finding software that says it can export site data into GML. I´m sure Autodesk- Civil 3D can do it, but I would rather not look in that direction…

Google search…

https://www.citygmlwiki.org/index.php/Freeware

And I guess CityGML and GML is the same ?