Constant MAX_AUTO_ANNOUNCE_INTERVAL_S 

pub const MAX_AUTO_ANNOUNCE_INTERVAL_S: u32 = _; // 86_400u32

Longest accepted PROP_ADVERT_INTERVAL / PROP_BEACON_INTERVAL, in seconds.

A ceiling on how stale the mesh’s picture of a node may get while that node still considers itself to be announcing. Past a day the schedule has stopped being one, and 0 says so more honestly.