I think this might come from a typical feedback on patches in Apache (or all of OSS) - -1 rejected as is, +1 approved. I've also seen -0 (don't approve but won'

I think this might come from a typical feedback on patches in Apache (or all of OSS) - -1 rejected as is, +1 approved. I've also seen -0 (don't approve but won't block/reject) and +0 (ok with it but didn't review/won't approve)