This subtemplate of {{BOOKPAGENAME}} handles for {{BOOKPAGENAME/core}} the case of category namespace.

လၢႆးၸႂ်ႉတိုဝ်း မႄးထတ်း

The two parameters expected are namespace and pagename.

Internals မႄးထတ်း

At this writing, the associated book name for a category is derived from the pagename by stripping an optional Book: prefix and treating the result as the full name (with namespace) of an in-book page, delegating through {{BOOKPAGENAME/refactor}} to {{BOOKPAGENAME/inbook}}.

If the Book: prefix becomes mandatory in the future, the optional-prefix-stripping could be modified to simply always strip off the first five characters, but it's not clear that making the code less able to handle contingencies is a fair exchange for vanishingly small cost savings, even if the contingencies aren't expected to happen anymore.