short term fuel trim

Welcome back to 2CarPros. That cannot be the actual fuel trim number. I would say whatever you are using to read the data is either reading the wrong signal or it is reading it inverted. Normal short term fuel trims on a good running engine will be around 1%. It also wouldn't be expressed as Bank 1 Sensor 2, but only as bank one or bank two.
B1S2 would be a designation for an oxygen sensor, but they don't read in percentage but in voltage.
What is the scan tool you are using?

this is the scan tool and the reading.

Launch has extra data PIDs in many of their tools. In this case it looks like they are reading something else. Notice that B1S1 is reading 0%. Is this with the engine running? If yes I would say it's extraneous data. The reason for that is that short and long term fuel trims both max out at around 24% on GM engines. 99% would flood the engine with fuel to the point it wouldn't run.

running at idle. here are some other readings. do they look okay?

It looks like it isn't fully warmed up. Looks to be in open loop so that makes many of the readings more or less unknowns. Until it goes into closed loop. But the ones on there look okay.

thanks for the information.

No problem. Take it out for a drive, once it's warm capture that data and post it here. Might see if it's good or not.

will do.