Comment 1 for bug 814667

I'd agree that "triangle" should be an name attribute, this would bring it into line with the mesh format options under geometry/mesh, which I'm guessing this was meant to emulate.

You'll need to change the code at assemble/Adapt_State_Prescribed.F90:109 from:
call get_option(base_path // "/mesh/from_file/format", format)
to:
call get_option(base_path // "/mesh/from_file/format/name", format)
though.

That format variable doesn't then actually seem to get used anywhere mind you but get_option will still throw an error if it can't find it.