[pcre-dev] Odd behavior of \k

In keeping with .Net and Python, \k introduces a backreference when
followed by <name> {name} or 'name'

But what (if anything) should \k match otherwise?

Does this make any sense? By itself \k is matching a capital U

And this pattern ^(\k)(\k)pqreeest$

tested against the subject UU

matches the first U

Tested with pcretest using pcre 8.11 aka 8.12 shared library under Windows.

Regards,
Sheri