Lifecycle API is a funny idiosyncratic name, invented by some young IT folks, to try to politically justify that the API is only responsible of the lifecycle of the Data itself but not of the data that flows through it, and that the API is not doing what it actually does i.e. Create Read Update Delete operations.
A funny API that was meant to be a global integration layer for content management, and resulted to be a mapping read only of four data fields (i.e. just the Read part of the CRUD).
It was not politically possible to call it global content API or global archiving API, it was not possible to call it with the original name of the API that it was copied and stolen from and therefore the funny name came along.
Lifecycle API is not an overlay/platform API, but just a CRUD interface on GAP