A typical scrollback cut and paste workflow for me is via this <ctrl-b>P mapping...

mjbrownie on April 28, 2020 | parent | context | favorite | on: Tmux for Mere Mortals

A typical scrollback cut and paste workflow for me is via this <ctrl-b>P mapping. I'm lazy I just grab everything.

   bind-key P command-prompt -p 'save history to filename:' -I '~/tmux.history' 'capture-pane -S -32768 ; save-buffer %1 ; delete-buffer'

then it's all in a file you can work with in an editor of your choice

nmarriott on April 28, 2020 [–]

You should be able to replace the capturep/saveb/deleteb dance with 'run "tmux capture-pane -p -S- -E- >%1"'