iPhone5,2_6.1.2_10B146_Restore.ipsw in Trash

A file named iPhone5,2_6.1.2_10B146_Restore.ipsw just appeared in my Trash today. I have an iPhone 5 I use with my 2008 White MacBook with OS10.6.8. The file is about 1gb and was created and last modified on Feb 13, 2013. To the best of my knowledge I did not move the file to the trash. Should I be alarmed? Do I need it, or is it okay to empty the trash?

Just for clarification I have not updated my iPhone or plugged it in for over a week. I cannot think of any actions I took to cause the file to move to the trash.