Is there a difference between typical a ZIP file and an APK file?

Question

I know a typical APK file would have AndroidManifest.xml but that's not the aspect I ask for. I'm asking in terms of ZIP structure and headers, ie at a lower level perspective.

Answer 1

Any APK file is a valid ZIP file. There's more to it than that - files that must be present, the fact that zipalign is normally used to align data structures within the file - but it's all valid ZIP.

Answer 2

AFAIK, it is a completely standard ZIP file. I have had no problems working with an APK as a ZIP file using any tool I have tried.

Note that, as with regular ZIP files, not all entries will be compressed (varies by file type).