Currently, any page on which Popups loads has most of its debuggability compromised due to the inclusion of an invalid //# sourceMappingURL statement half-way in the combined debug=false bundle pointing to a file that doesn't exist (/w/index.js.json).
I understand its purpose is to, in debug mode, allow source maps to work (which is pretty useful). However for all other code in production that is not Popups, no source maps are involved, and generally in day-to-day work, production mode is a better debug mode (Yeah, T85805 for more).
Please ensure this comment is removed in production mode. Right now this is not happening because of the inclusion of a @nomin instruction in the dist build (added in 7bd29bb). I'm not sure why that is, as it appears to directly (and only) lead to this bug :-)