The version floor each peer is held to, and the node-wide handshake counters (docs/design/WIRE_1_0.md sections 4.6 and 8).

A node records, per peer node_id, the highest handshake version it completed with, and never completes below it. The floor is raised only after a handshake completes, and only upward. It survives restarts through the connection's version_floor option, a store {Mod, Arg} with Mod:floor(Arg, NodeId) -> Version | none and Mod:raise(Arg, NodeId, Version) -> ok | {error, term()}. Without one, a node keeps the floor for the run, as an SDK host with no writable store does. A raise the store fails to persist keeps the completed connection and the floor in memory, and counts and logs version_floor_unpersisted; it never crashes the node or closes the link.

The table belongs to macula_peering_sup, which creates it with new_table/0 and holds every connection that reads it, so the memory lasts as long as those connections can, whichever child of that supervisor dies (macula#50). There is no process here: every read and write goes to the table directly, so no connection queues on it.