Function pane_path_segment 

pub fn pane_path_segment(
    pane: &PaneState,
    rs: &RenderState,
    provider_label: Option<&str>,
) -> String

The buffer-label segment for pane: a pane provider’s custom label when one is supplied (provider_label — the file-tree / oil / help M.4 mechanism, resolved renderer-side and passed in so the assembly stays common), else the document path + dirty marker (or the registry name slot for non-document panes). Empty only for the genuinely-nameless case, which the caller treats as hidden.