Blocks 199462-199465 were all created within a minute of each other, sequentially. Is that a function of how busy the network is or is it a decrease in difficulty?
Random chance. Sometimes miners find a new block within seconds of the previous block. Sometimes miners find the next block an hour or two after the previous one.
10 minutes is only the average target.
Miners choose which transactions to include in a block.
A valid choice is "no transactions" [besides the required coinbase transaction].
I now grok the no transactions flag. Thanks.
Not sure what you mean by "flag" but ok