Then we are near to a solution. Beeing compatible with C Git is a
valid argument for me. I was just not aware about 'git for-each-ref'
functionality regarding ORIG_HEAD, FETCH_HEAD or
MERGE_HEAD. Just for being compatible I agree that
repo.getAllRefs() should not return the implicit ref-like things
ORIG_HEAD, FETCH_HEAD and MERGE_HEAD (only HEAD
will be returned by getAllRefs()).
My suggestion: if we would add a 'getImplictRefsNames()' or even
only expose a 'public static String[] implicitRefsNames' to the
RefsDatabase my problem is solved.