This reports the number of cryptomap entries contained in this dynamic cryptomap, per its description - essentially how many distinct policy templates (each potentially with different transform sets or ACLs) exist within one dynamic cryptomap for matching against incoming, unpredictable peer connections. A dynamic cryptomap with a size of 1 can only match one type of incoming connection profile, while a larger size can accommodate a wider variety of spoke configurations connecting to this hub. An admin adding support for a new type of remote peer would need to add an entry here, increasing this size.