I'm familiar with chess notation, but this has left me scratching my head. Looking at this answer, I see two games ending with moves marked as "+-" or "-+" (plus-minus or minus-plus). What does this annotation mean? Is it standard? And why are the two games using it with the symbols in different order?
Wikipedia does not mention this symbol, and I find searching for it quite difficult. Looking at the two boards allows me to rule out plenty of things - it's not check, checkmate or stalemate - but doesn't decisively reveal what it is. Is this perhaps some indicator of positional advantage (which I can see on both boards)?