As noted in issue symfony/symfony#5869 the Routing documentation is a little unclear as to when routes with optional parameters at the end are matched.

my_test_homepage:
    pattern:  /hello/{name}
    defaults: { _controller: MyTestBundle:Default:index, name: DefaultName }

The above route will only match on /hello and /hello/name, it will not match /hello/. I would like to clarify this in the documentation to avoid any confusion in the future.