difference between x and k

what's the difference between x and k? Shoulnd't k mean a public key for a single private one, while x be a public for some "master" key of the BIP-32 wallet?

These are different prefixes. They affect the key generation . Bitcoin uses xpub xprv and tpub tprv for testnet.  Kaspa uses its own prefixes kpub and kprv.  If u change the prv prefix then it will change the key. Kaspa also has tprv, sprv and dprv. … but the current wallet framework doesn’t use them. The idea is that you can’t mix keys between networks and accidentally send real funds when u think you are on testnet. It’s in one of the BIPS (afk, don’t remember which one). They are supported by the framework but not used in key generators. (I.e. current wallet SDK will use kprv regardless of the network.).  We might add them later on, not sure.