The window-utils and observer-service modules allow access to relatively unsafe and unstable Gecko innards in the same way as require("chrome"). They allow add-ons to leak in difficult to detect ways and to use APIs which are likely to change. Imports of those modules should be flagged the same as require("chrome") and the add-ons should be kept from the Fast Track queue. CCing the editors from the Jetpack team in case there are other modules which should be treated similarly or they have other input.
Fixed: https://github.com/mozilla/amo-validator/commit/76ac7c135e2381d7ece875d2377148de978ea967 Pushed to AMO: https://github.com/mozilla/zamboni/commit/e3f1f1a