$WALLET and xWALLET are two tokens that serve different purposes in the Ambire ecosystem. While $WALLET is a token which is used to reward users of Ambire wallet and can also be traded, xWALLET represents the share you have in the $WALLET staking pool. When you stake $WALLET you get xWALLET as a representation of your staking position. This means that xWALLET holders will be able to vote in the WalletDAO and the two tokens are interconnected through the staking mechanism.
At first, when the staking pool was launched, 1 xWALLET = 1 $WALLET. Then the pool accrues 10% yield in the first year, so the ratio is now changed and 1 xWALLET = 1.1 $WALLET (10% more). E.g. as stakers accumulate rewards, the value of their xWALLET increases. This happens because the amount of xWALLET tokens a staker holds remains the same but their value increases as they accumulate staking rewards.