One comment made in the forum with which I agree is
The next version of the Seamly2D schema could (should) declare an XML namespace - I’m happy to help design this change. The code could then easily differentiate between Seamly2D and Valentina files. (@MrDoo)
Does anyone have comments or discussion before I add this as an issue on Github?
Simply adding a namespace to the existing schema, just for the sake of it, has lots of disadvantages: backward compatibility, supporting both schemas through transition, testing etc.
The suggestion arose regarding taking the seamly XML schema forward independently of Valentina. When we need to create the next version of the seamly XML schema we should declare a namespace at that point. We will then find ourselves supporting (at least reading) multiple file formats through a transition period.