How do I bridge FXS from arbitrum back to mainnet?

We don't support swapping FRAX between wrapped bridge assets after FIP100, we're in the process of deprecating all that but If you have canonical FRAX or canonical FXS, you will be able to redeem for Ethereum mainnet FRAX and FXS eventually so rest assured 💪 https://gov.frax.finance/t/fip-100-remove-all-canfrax-canfxs-swaps-between-bridges-remove-bridge-frax-fxs-pol/1749