They show up in the widgets list with the same name. The global menu lacks a description which makes things more confusing. One of the two should be renamed. Maybe Global Menu should be just "Global Menu" with a description like: "Move the the application menu bar out of applications into this widget."
Duplicate of https://bugs.kde.org/show_bug.cgi?id=375478 ?
*** This bug has been marked as a duplicate of bug 375478 ***