Function derived 

pub(crate) fn derived(list: &str, what: &str) -> String

The id format 2 gives an element without one: from its list and what, the stable key format 1 named it by (identity: a session’s start, task and project; a money line itself), the same on every device. Written into the element once, when the device takes format 2 (switch_format); until then, and for an element made without one since (by hand), its name. Shaped as a UUID (version 8: made here, by name).