This is really impressive! Since they didn't have a comparison to foot, I ran it on my machine with sway. Here are my results:

Kitty old run #1
Results:
  Only ASCII chars         : 6.01s      @ 33.3    MB/s
  Unicode chars            : 5.12s      @ 34.6    MB/s
  CSI codes with few chars : 4.94s      @ 20.3    MB/s
  Long escape codes        : 18.08s     @ 43.4    MB/s
  Images                   : 2m12.09s   @ 4.0     MB/s

kitty new:
Results:
  Only ASCII chars         : 2.36s      @ 84.8    MB/s
  Unicode chars            : 2.06s      @ 86.0    MB/s
  CSI codes with few chars : 2.05s      @ 48.8    MB/s
  Long escape codes        : 3.68s      @ 213.0   MB/s
  Images                   : 2.28s      @ 234.4   MB/s

foot:
Results:
  Only ASCII chars         : 1.72s      @ 116.3   MB/s
  Unicode chars            : 2.51s      @ 70.6    MB/s
  CSI codes with few chars : 1.31s      @ 76.2    MB/s
  Long escape codes        : 5.48s      @ 143.0   MB/s
  Images                   : 2.44s      @ 218.2   MB/s

Kitty old run #2 (after all other runs, to see if poor performance was a fluke)
Results:
  Only ASCII chars         : 44.84s     @ 4.5     MB/s
  Unicode chars            : 19.11s     @ 9.3     MB/s
  CSI codes with few chars : 34.58s     @ 2.9     MB/s
  Long escape codes        : 14.06s     @ 55.8    MB/s
  Images                   : 2m12.08s   @ 4.0     MB/s

I expected foot to win, and it does win for Only ASCII chars and sci codes by a little bit, but not by much, and not by a meaningful amount, especially when you consider all the other features kitty has. Great work!

Also, this wasn't a very rigorous test. I had a bunch of other stuff open, and I just ran them one after the other without much cooldown

How do you run the benchmarks? kitten __benchmark__ says "__benchmark__ is not a known subcommand for kitten"

Edit: I see now that the changelog says that the benchmark kitten was added in this release