Function session_text 

pub fn session_text(
    rows: &[Row],
    limit: usize,
    colour: bool,
    fmt: Fmt,
) -> String

Spend per session, newest first. The Csv form is one row per session (session,requests,tokens_in,tokens_out,cache_read,cost_usd), Json a {scope,source,sessions} object whose entries add the last-used instant and the distinct-model count; Table keeps its own (last, models) columns.