A diff like:
diff --git a/tests/wpt/web-platform-tests/2dcontext/transformations/2d.transformation.order.html b/tests/wpt/web-platform-tests/2dcontext/transformations/2d.transformation.order-new.html
similarity index 100%
rename from tests/wpt/web-platform-tests/2dcontext/transformations/2d.transformation.order.html
rename to tests/wpt/web-platform-tests/2dcontext/transformations/2d.transformation.order-new.html
gets excluded when I run filterdiff -p 1 -i tests/wpt/web-platform-tests.