How fast blocks spread and how stable the chain tip is, from the status page: propagation reports with median, p90 and p99 delay (ms) after the first node saw a block, the median time for recent blocks to reach 90% of verified nodes and any consistently slow miner, delays by band; stale blocks in the last 2,000 heights, reorganization count and the last and last deep (3+ blocks) reorg with height, depth and time, and any chain split.