MooseX-Types is managed using Dist::Zilla which rewrites some of the source code when it gets published. In the MooseX-Types repository on Github, there is no $VERSION defined at all; this is added when it gets published. When Dist::Zilla adds $VERSION lines it always does so right underneath the package statement, thus it ends up above the use strict line.

I'm not quite sure of the reason for the block. Possibly Dist::Zilla has a policy of wrapping any inserted code in a block to prevent lexical leakage; in this case there would not be any leakage anyway, but perhaps such a policy is automatically applied to all inserted code.