This is a modified binary-to-text encoding used for encoding Bitcoin addresses, aka Base58Check. If this is applied to an extended private key with its trailing check sum, then the result is the Wallet Import Format, (WIF).
base58CheckEncode(x)character, string in hex format.
character, the encoded string.
https://en.bitcoin.it/wiki/Wallet_import_format, https://en.bitcoin.it/wiki/Address, https://en.bitcoin.it/wiki/Base58Check_encoding
Other BtcAdresses: BTCADR-class,
PrivKey2PubKey, PrivKey2Wif,
PubHash2BtcAdr,
PubKey2PubHash, Wif2PrivKey,
base58CheckDecode, concatHex,
createBtcAdr,
createPrivateKey, decodeHex,
hash160, hash256,
validBtcAdr