C-Lightning PRs #2541, #2545, and #2546 implement multiple changes to the gossip subsystem used for tracking which channels are available and calculating routes across them. This work was motivated by the million channels project and performance results from that project are included in many of the commit messages. If Optech is interpreting the results correctly, the difference between the first commit in the series and the last commit is an 79% reduction in memory use, from 2.6 GiB to 0.6 GiB, and an 80% reduction in the time to build a route to a randomly-selected node (within 20 hops) from 60 seconds to 12 seconds. (If even the improved values seem high, recall this is for a simulation network more than 25 times the size of the current mainnet network and 1,000 times the size of the network a bit over a year ago.) A notable part of this change is C-Lightning switching from its rather unique Bellman-Ford-Gibson (BFG) routing algorithm to a slightly-customized version of Dijkstra.