Constant forest_actor::miner::MAX_SECTOR_EXPIRATION_EXTENSION

pub const MAX_SECTOR_EXPIRATION_EXTENSION: i64 = 540 * EPOCHS_IN_DAY; // 1_555_200i64

Maximum number of epochs past the current epoch a sector may be set to expire. The actual maximum extension will be the minimum of CurrEpoch + MaximumSectorExpirationExtension and sector.ActivationEpoch+sealProof.SectorMaximumLifetime()