midi2 is a small piece of infrastructure for boards that already have too much to do. Sound chips, displays, USB stacks, sensors, network. MIDI 2.0 arrives at the transport layer as 32-bit words; midi2 turns those words into structured events and stays out of the way the rest of the time.
The library implements 100% of the UMP format (M2-104-UM v1.1.2) and 100% of MIDI-CI (M2-101-UM v1.2). The application owns memory and decides which modules to link. The transport (USB, BLE, network, serial) lives somewhere else, by design.