Test::Builder2: running coverage fails to display key modules

[James E Keenan]

When I run Devel::Cover over the Test::Builder2 test suite 
(v1.005000_001-193-g00d4609), I get no coverage reports for 
blib/lib/Test/Builder2.pm or blib/lib/Test/More.pm.

See:  http://thenceforward.net/test-more/coverage/coverage.html
Any thoughts on why that is happening?

Thank you very much.
Jim Keenan