Somebody mentioned their inactive github but very active CEX listings. website confirms https://sierracoin.net
Scammers Profile Link:
https://bitcointalksearch.org/user/sierracoinfoundation-2446298
Reference Link:
https://bitcointalksearch.org/topic/annsirrasirracoin-join-the-solar-mining-revolution-mnposspow-5055663
Additional Notes:
their code base would not pass the audit with errors like https://github.com/sierracoin-foundation/sierra/blob/master/src/chainparams.cpp#L149 (1977 is xumacoin) so this is clearly unqualified team working for PnD?
dev team clearly not capable to keep the core updated and compile-able so there is no binary distribution - this a common scam releases page
https://github.com/sierracoin-foundation/sierra/releases