REGARDING IDP APIs

Hello @IntegrationSupport
i have gone through IDP
IDP LINK

https://sandbox.abdm.gov.in/docs/identity_service_provider

but i got lost here
i really want to understand the role of IDP in ABDM structure and where actually it fits
i mean does it belong to M1 integration or M2 or M3 ,may be PHR
from where can i read or get more details for this

Regards
Deep