I tried it today on some files using an Epubcheck 3 validation. It does not work anymore: I get this message. FlightCrew does not care about this.
Epubcheck Version 3.0
ERROR: À grandes guides v2.epub: Length of the first filename in archive must be 8, but was 45
Validating against EPUB version 2.0
Check finished with warnings or errors
Note: using Linux.