Function transcript_rows 

pub fn transcript_rows(
    config_dir: &Path,
    session_id: &str,
    cwd: &str,
    below: Option<&TranscriptAnchor>,
    rows: usize,
) -> Option<TranscriptSpan>

The rows of a session’s transcript that sit strictly before below, for a paging read that has walked below the window a conversation is kept in.

session_history is the whole file and answers what a session IS; this is a page of it and answers what a page needs. below is the row the page above stopped at - the id it carries and, once a read has seen it, the byte it starts at - and None reads the file’s own newest rows, which is the walk’s first ask on a window that holds no row to name.