Issue with tmux update

[Ergus]

Hi,

After my system updated tmux to version 3.5 on October 1st, I noticed
that the keybinding combination "C-M-/" (which I use for undo-redo) has
stopped working in certain setups.

Here’s what I’ve observed:

When I try `emacs -nw` followed by `C-h k C-M-/`:

xterm: Works fine
xterm + tmux: Works fine

foot: Works fine
foot + tmux: Outputs M-[ 2 7 ; 7 ; 9 5 is undefined

alacritty: Works fine
alacritty + tmux: Outputs M-[ 2 7 ; 7 ; 9 5 is undefined

kitty: Works fine
kitty + tmux: Outputs M-[ 2 7 ; 7 ; 9 5 is undefined

I primarily use foot or alacritty because I’m on Wayland.

Regardless of the terminal, when I run `cat` in any of these shell/tmux
combinations, I get the same output: ^[^_.

Interestingly, these combinations work as expected:

foot + tmux + `TERM=foot emacs -nw`: Works fine
foot + tmux + `TERM=xterm emacs -nw`: Works fine

Given these mixed results, I’m unsure if the issue lies with Emacs,
tmux, or something in my configuration.

Any insights or suggestions would be greatly appreciated.

Thanks,
Ergus