For API documentation see the versioned API documentation site.
This is documentation for libbpf, a userspace library for loading and interacting with bpf programs.
All general BPF questions, including kernel functionality, libbpf APIs and their application, should be sent to email@example.com mailing list. You can subscribe to the mailing list search its archive. Please search the archive before asking new questions. It very well might be that this was already addressed or answered before.