Docs

Accounts

An account id is 20 bytes, the same width as the account id people already know from other chains. What changed is the way it is written down. The label is KAL, then 40 hex characters. The checksum starts after those three letters, so the A in KAL is not a character you can flip to change the checksum.

A parser on this chain accepts the KAL form and an older one-letter form. What the chain shows you is KAL. A 64-byte address from somewhere else is not an account here.

XMSS, said once more because it matters

If the account signs with XMSS, the signer has to remember which leaf it used. One leaf, one signature. A wallet that forgets that state, or two copies of a wallet that both think they own the next leaf, will destroy the account. The browser wallet keeps the seed in the tab and can write it into an encrypted file. Close the tab, or open the same file in two places and send from both, and you are back in that trap. The seed is 51 bytes. There is no word list to recover it from.

Contracts

An address can hold code when a spending account publishes bytecode from the wallet. The writing rule is on the contracts page. The explorer stores the code bytes. A checked source listing is a separate step, and this explorer does not do that step.