If you wish to give access to the add-on to more than just network admins, use the broadcast_menus_access filter.
Child post ID translation
If a menu item on the source blog points to a broadcast post, and the post exists as a child on the target blog, then the menu item URL is modified to point to the child post.
The the broadcasted post has not been broadcasted to the target blog, the menu item is converted to a custom URL pointing to the source blog.
The cleanup tab can be used to delete duplicate items, or invalid items.
Duplicate a menu
If you wish to duplicate a menu, in the menu item manipulation tab: select the item you wish to duplicate, select the same blog you are on and choose the rename action.
This feature is used when one wants to insert / remove broadcasted menu items from lots of child blogs. The menu item will be broadcasted and its place in the menu, parent and order wise, will be exactly duplicated on each child blog.
Similarly, if a taxonomy (category, tag, etc) on the source blog exists on the target blog, the URL is modified to point to the taxonomy on the target blog.
If no taxonomy with the same slug is available on the child blog, the menu item is converted to a custom URL pointing to the taxonomy on the source blog.
The link you followed has expired
If you see this error message when copying or manipulating menus, you’ve got a conflict with a theme or plugin. If the fix snippet doesn’t solve your problem, you’re going to have to debug the problem by selectively disabling plugins or themes until the error disappears. Then contact me to see if I can make the fix permanent.
If you are using UberMenu menu segments or dynamic posts, you might want to look at the Broadcast UberMenu add-on.
If your menu does not come out the way you want it, try disabling WPML? There seems to be a conflict with that plugin when copying menus as of 2020-05-28.