Application for making SIP voice calls in main?

[Alexander Konovalenko]

Does Ubuntu 10.04 LTS include a SIP client that is capable of making
voice calls?

There are many in the *universe* section: Ekiga, Kphone, Linphone,
QuteCom (former WengoPhone), telepathy-sofiasip (which adds SIP voice
call support to Empathy), and Twinkle.

But is there any SIP client in *main*, officially supported for
3 years with security and other important updates?

Empathy can't do SIP voice calls in the default configuration in
Lucid. It needs telepathy-sofiasip for that, but telepathy-sofiasip is
in universe. Pidgin supports only XMPP/Gmail/Google Talk voice calls,
but not SIP (according to the official FAQ). Please correct me if I'm
wrong here.

It's interesting that the official documentation still recommends
Ekiga as the VoIP client [1], despite the fact that it is no longer
supported by Canonical since Lucid [2].

[1] https://help.ubuntu.com/10.04/internet/C/internet-instant-messaging.html#internet-instant-messaging-ekiga
[2] http://packages.ubuntu.com/lucid/ekiga

I will be grateful for any pointers. For example, does anyone know
why Ekiga has been removed from main, but telepathy-sofiasip
hasn't been added?

What's the plan for Maverick and beyond? Will Ubuntu include a SIP client
in main?

 -- Alexander