Approval Distribution Subsystem

roadmap/implementers-guide/src/node/utility/network-bridge.md

@@ -61,6 +61,12 @@ The `activated` and `deactivated` lists determine the evolution of our local vie
 
 If we are connected to the same peer on both peer-sets, we will send the peer two view updates as a result.
 
+### Overseer Signal: BlockFinalized
+
+We obtain the number of the block hash in the event by issuing a `ChainApiMessage::BlockNumber` request and then issue a `ProtocolMessage::ViewUpdate` to each connected peer on each peer-set. We also issue a `NetworkBridgeEvent::OurViewChange` to each  event handler for each protocol.
+
+If we are connected to the same peer on both peer-sets, we will send the peer two view updates as a result.
+
 ### Network Event: Peer Connected
 
 Issue a `NetworkBridgeEvent::PeerConnected` for each [Event Handler](#event-handlers) of the peer-set and negotiated protocol version of the peer.

roadmap/implementers-guide/src/types/network.md

@@ -8,7 +8,12 @@ These types are those that are actually sent over the network to subsystems.
 type RequestId = u64;
 type ProtocolVersion = u32;
 struct PeerId(...); // opaque, unique identifier of a peer.
-struct View(Vec<Hash>); // Up to `N` (5?) chain heads.
+struct View {
+	// Up to `N` (5?) chain heads.
+	heads: Vec<Hash>,
+	// The number of the finalized block.
+	finalized_number: BlockNumber,
+}
 
 enum ObservedRole {
 	Full,