[sr-dev] uac_reg module use of l_uuid in Contact header

I've been trying to work out how to set the username element of the contact header in uac_reg outbound REGISTER requests and it seems it's hard coded in the source (uac_reg.c:990) to use the l_uuid. I'm curious why l_uuid is used here and not l_username which feels like it should be more consistent with the use of r_username? My C skills are sufficient to let me patch this locally for my application, but I wondered what the reason for this design decision is or if it's actually a very long lived 'bug' as it feels like l_username is the 'right' thing to use here? Alternatively, perhaps this would be considered a feature request to make it configurable via another parameter in the database (probably beyond my C unless I modelled it on the pull request that added contact_addr (#2470) Ross