I want to make sure that River2 is writing static files through the OPML Editor's mechanism for static files.
It appears as if it is. Look in river2suite.static.writefile. It calls opmleditor.writestaticfile. Now I want to test this in practice, by installing River2 on a virgin server, configure the static file facility in the OPML Editor, and verify that the static files are written to the correct location.