Convert every file whose kind is "Mariner Write document"

I like Mariner Write, but it no longer works on newer machines and I need to upgrade soon. I have 1,300 Mariner Write documents that I want to convert (probably to rtf) so I don’t lose access when I upgrade.

I have thought of writing some recursive script to walk all the folders, but I think it would be easier to get a list of all 1,300 file/folder locations and tell Mariner Write to convert each one that way.