Variable: EPOCH_SIGMA_DISPLAY_SECONDS

const EPOCH_SIGMA_DISPLAY_SECONDS: 10 = 10;

The threshold at which the epoch's clock-error uncertainty becomes visible at the app's display scale: 10 s of sigma is ~2.5 arcmin of angle smear, the point a reading would show. Below it, canonical output carries no epoch-sigma block, so modern charts' digests are unchanged.