Sorry if my question is answered all over the site/forums, I looked in the Wiki, in the FAQ and searched the forums, but couldn't find anything relevant.
I'm talking about the queue ratings, displayed in the Priority column when a download is expanded.
Most of them are black and have a zero between brackets, looking like this:
QR: 213 (0)
but some are colored in red or blue and have a positive of negative number between brackets, like:
QR: 207 (-27)
or
QR: 29 (2)
What do the colors and numbers between brackets mean? Thanks.