The openscreen project relies on Ubuntu 16.04 bots in luci.flex.ci and luci.flex try.  Around 1pm PST this afternoon, our CQ started hanging and I noticed there were no bots (neither offline nor busy).  The bot was added from issue 896341 and I don't see that any commit removed it, but it doesn't seem to be available when looking on chromium-swarm.appspot.com either.