What is a .s12 file (bios related)

After launching the hp bios updater utility you will have the option to save the bios rom somewhere on the system drive, and it would create 2 files, the .bin file and an additional .s12 that makes me think my life choices. The weird thing is that if I extract the executable of the utility I can find the .bin file but there’s not a single trace of that .s12 file.

04/29/2021  02:26 PM        16,777,216 085FA.bin
04/29/2021  02:26 PM               256 085FA.s12

Is it just a signature? What does it stands for? Thanks in advance!