I have been trying out and liking Kitty as an alternative to iTerm. But I was missing the Cmd-Shift-V “Paste current selection” behavior from iTerm. After a few false starts I found the config necessary spelled out in the default config file.

#: Copy to clipboard or a private buffer on select. With this set to
#: clipboard, selecting text with the mouse will cause the text to be
#: copied to clipboard. Useful on platforms such as macOS that do not
#: have the concept of primary selection. You can instead specify a
#: name such as a1 to copy to a private kitty buffer. Map a shortcut
#: with the paste_from_buffer action to paste from this private
#: buffer. For example::

  copy_on_select a1
  map shift+cmd+v paste_from_buffer a1