The Partisia Blockchain (PBC) innovates blockchain technology by bringing an extra layer of privacy where it's needed. This allows Zero Knowledge computations to happen in parallel of the regular transactions. This, combined with Multiparty Computation, allows more complex scripts to run, while being more private at the same time.
Partisia also allows anyone to easily transfer their own assets from other blockchains into PBC. In the system they called "Bring Your Own Coins" (BYOC), you can lock assets in the PBC Token Bridge and mint the same amount as a PBC version of that asset. As compensation to this service provided by nodes, they keep 0.1% of all assets being bridged. For example, if you bridge 1 ETH, then 0.999 ETH is transferred and 0.001 ETH is paid to the oracle nodes. Koala Wallet itself doesn't charge or keep any of this value.
The opposite is also possible, by invoking the Bridge smart contract, which will burn the tokens on PBC and releasing their counterpart on the original blockchain. Bridging in and out of PBC is natively built into Koala Wallet which you can read more about here.