See for example inspecting a `Record` on chrome:  versus on macos:  This is because the library (and therefore the library URI) for the `evaluate` request is `null`: https://github.com/dart-lang/webdev/blob/7543345873b4ea4457a584a86677b38755001d9d/dwds/lib/src/services/chrome_proxy_service.dart#L626 FYI @annagrin