Questions about the my Foo $var syntax

There's some legacy syntax still used in some very old code bases, e.g. 
TheSchwartz

   my TheSchwartz::Job $job = shift;

As far as I can tell, this doesn't do anything except require that 
TheSchwartz::Job namespace exists. It doesn't require $job to be a 
TheSchwartz::Job.

I have some questions:

1. Is this documented anywhere still?

2. Is the syntax deprecated?

3. if not, are there plans to do something useful with it, e.g. enforce 
type constraints?

• Questions about the my Foo $var syntax by Robert Rothenberg
• Re: Questions about the my Foo $var syntax by Kang-min Liu
• Re: Questions about the my Foo $var syntax by Dave Mitchell
• Re: Questions about the my Foo $var syntax by Paul "LeoNerd" Evans
• Re: Questions about the my Foo $var syntax by "Ruud H.G. van Tol" via perl5-porters
• Re: Questions about the my Foo $var syntax by demerphq