Hi Dan,
The menu_id is the id of the menu this menu item will become a part. The target is the id of the iframe/tab the menu item will populate. So menu items belonging to menu_id phb0 can all target the id/named flb tab or target different tabs but all are a part on the menu: pfb0.
The requirement i’m unsure. My guess it is for context i.e requirement: 1 may mean if item exist. or 0 always. I’m just guessing on this and review of code should give insight. If you do track requirement down, be nice to share here for us…