Iíve got my Pi3 working :-)

I can see folders showing up on the screen that shows video output from my Pi3. Can anyone here on this forum tell me what the name of this Windows File Explorer-like software is?

Am I correct that the operating system that came with this SD card is Raspian? How can I confirm that the O/S used by my Pi3 is Raspbian?

Many thanks in advance for your assistance,
Barry.