Function own_pane_by_token 

pub(crate) fn own_pane_by_token(
    store: &Store,
    caller: Option<&Caller>,
    name: &str,
) -> Option<String>

Identity M4d-4: the pane of a caller whose token names it under its own slug, from its UID’s registration, with no key to check. None (today’s name path) for anyone else, or before the UID registers.