I stumbled upon an issue mentioned in this Kindle thread
The user defined an embedded font in the <style>
section of an .html file and got the following FlightCrew error:
This resource is present in the OPF <manifest>, but it's not reachable (it's not unused).
However epubcheck doesn't report any errors and the embedded font shows up in ADE and KP (after compilation).
When I moved the style segment to a separate stylesheet and linked it to the .html file, FlightCrew no longer reported the error.
Here's the code:
Is this a feature or a bug?