sLSTR = staked LSTR (the governance token for LeoStrategy). When you convert RWA tokens via RCBF, you send them to @rcbf on Hive-Engine, and within 24 hours you receive sLSTR to your Hive-Engine wallet — not Arbitrum. The sLSTR has a 7-day unstaking period if you want to convert it to liquid LSTR. Per @leostrategy's RCBF announcement, the rate is published by the yield agents like @tgld.yield.