Assuming this is implemented, how does it work in case of Californians traveling in other states/countries? Will it work like the current out-of-network case, t

Assuming this is implemented, how does it work in case of Californians traveling in other states/countries? Will it work like the current out-of-network case, that the government reimburse you some percentage, with some restrictions (ER only, for example)? Or will the Californians need to buy a separated insurance before they travel? How does this work for single-payer countries, like Canada?