In version 0.9.9a it was possible to type a link-local multicast ipv6 address (like ff02::1) into the address field of the 'open media -> network' dialog and add a device name as it is necessary for link-local ipv6 connections (like ff02::1%eth0) in the MRL field with 'Show more options' enabled.
In version 0.9.9a the ipv6 address in the MRL field was auto-magically surrounded with brackets.
The editing in the MRL field was necessary because of typing the '%' character into the address field expanded to a '%25'.
In 1.0.0-rc2 the editing of the MRL field isn't possible and the brackets around the ipv6 address also aren't set.
Now it is not possible to open a address like 'rtp://@[ff02::1%eth0]:1234' with the open dialog.