Great news: I sent a message to CryptoSlate with the new website and Twitter feed, and someone wrote back to say they'd update it -- and they already have!
XSTC is no longer identified as being in the "Abandoned" category (although there is still a box on the page that says that, for now). Now if we could only see what the current price is...

https://cryptoslate.com/coins/safe-trade-coin/