The webrtc binding of the Transport SPI (spec §5.5, SRAD srad/agentspaces-js.md §3.4, §3.5): one RTCPeerConnection per peer connection with one ordered, reliable data channel (aspace/1), signalling over the aspace:cap/rtc-signal capability pipe, and attestation by the DTLS fingerprint each side signs into its signal. The engine sits behind the DataChannelEngine seam; the first engine is libdatachannel-java, whose native library this module alone carries.