That said they have done a few bugfix revisions, RP2040-B0 is the original, -B1 has some refinements to the ROM code, and -B2 has further ROM changes and also f

That said they have done a few bugfix revisions, RP2040-B0 is the original, -B1 has some refinements to the ROM code, and -B2 has further ROM changes and also fixes some silicon bugs from the earlier versions. If you're using the official SDK you probably don't need to care too much about which version you have though, because the standard high level libraries detect the hardware revision at runtime and enable or disable workarounds as needed.