The idea is to highlight completed torrents that have no chance to continue seeding (all trackers are disabled or have error state and none of which are timeouts) with red. Highlight torrents which seeding may continue automatically soon (all trackers are with error or warning state but some errors are timeouts) with some greenish. And to highlight torrents that supposed to be seeding but still have some warnings (all tracker states contain warning messages) with some yellowish.
In case at least one tracker reports OK state with no warning - it will be left green as default.
I'm not sure in color scheme and going to test a few things a bit more.
Ideally there shall be a setting to change colors.
P.S. I've found out that some bittorent trackers may return "Torrent is not registered" message under "warning message" key instead of "failure reason", but I believe this is a server side problem and misusing of BEP.