How the fileDescriptor variable is calculated?

[RandCNX]

Can someone point me how the fileDescriptor_ef5b54da0baffa1e variable is calculated?

I mean the variable on the .pb.go files. ex:

var fileDescriptor_ef5b54da0baffa1e = []byte{
// 172 bytes of a gzipped FileDescriptorProto
0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0x92, 0xcb, 0x4c, 0xcf, 0x4d,
0xd3, 0x2f, 0x4a, 0x2d, 0x4e, 0x2d, 0x2a, 0x4b, 0xd5, 0x2f, 0xae, 0x2c, 0x2e, 0x49, 0xcd, 0x8d,
0xcf, 0xcc, 0x4b, 0xcb, 0xd7, 0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0xe2, 0x01, 0xc9, 0xeb, 0x41,
0xe5, 0x95, 0x12, 0xb8, 0xb8, 0x82, 0xc1, 0x4a, 0x3c, 0xf3, 0xd2, 0xf2, 0x85, 0x14, 0xb8, 0xb8,
0x4b, 0x12, 0x8b, 0xd2, 0x53, 0x4b, 0x02, 0x8a, 0x32, 0x93, 0x53, 0x25, 0x18, 0x15, 0x18, 0x35,
0x58, 0x82, 0x90, 0x85, 0x84, 0x0c, 0xb8, 0x84, 0x73, 0x33, 0xf3, 0x9c, 0xf3, 0x73, 0x12, 0x4b,
0x52, 0x8b, 0x12, 0x73, 0x32, 0xab, 0x12, 0x4b, 0x32, 0xf3, 0xf3, 0x24, 0x98, 0xc0, 0x2a, 0xb1,
0x49, 0x39, 0xe9, 0x9d, 0x78, 0x24, 0xc7, 0x78, 0xe1, 0x91, 0x1c, 0xe3, 0x83, 0x47, 0x72, 0x8c,
0x13, 0x1e, 0xcb, 0x31, 0x5c, 0x78, 0x2c, 0xc7, 0x70, 0xe3, 0xb1, 0x1c, 0x43, 0x94, 0x08, 0xd8,
0xa5, 0x15, 0x70, 0xb7, 0x96, 0x54, 0x16, 0xa4, 0x16, 0x27, 0xb1, 0x81, 0x9d, 0x69, 0x0c, 0x08,
0x00, 0x00, 0xff, 0xff, 0x48, 0xa2, 0x08, 0xb3, 0xc8, 0x00, 0x00, 0x00,
}

Sorry I have no clue how this works.

[RandCNX]

I just noted that ignite updates it automatically.