wezterm/docs/config/lua/pane/get_user_vars.md

pane:get_user_vars()

Since: 20210502-130208-bff6815d

Returns a table holding the user variables that have been assigned to this pane.

User variables are set using an escape sequence defined by iterm2, but also recognized by wezterm; this example sets the foo user variable to the value bar:

printf "\033]1337;SetUserVar=%s=%s\007" foo `echo -n bar | base64`

you're then able to access this in your wezterm config:

wezterm.log_info("foo var is " .. pane:get_user_vars().foo)