etrex 20 base camp

HI all,
just a silly question of a newbie. I installed base camp with etrex 20 usb connected and afterward I checked filesystem and I found one file of over 3 GB size ( now only few MB left free )
I don't know if base camp installed this map file without asking kind of automatically or if it was already by factory filesystem.
Can you tell me if I can cancel it out with or without problem ?
Thank you in advance.
Denis