Function kept_back 

pub fn kept_back(block: &Collection, list_account: &str, chosen: &str) -> bool

Whether a time block kept on this device alone (block, its calendar) goes to its task’s server (21 October 2026): the task’s list is a server’s (list_account), so the task reaches your other devices while its time, here alone, would not, and the agendas would differ. Unless you chose that calendar for blocks (Tasks ⚙, chosen, “account/id”).