We have an app with a manual packaging process (MakeAppx.exe). We would like to publish this app to the Store including the public symbols files, so that I can download the .cab process dump file for crash analysis (such as described here).
I understand the .appxupload is a zip-file contaning the .appx package and an .appxsym file, which in turn is a .zip file containing the .pdb files (also according to MSDN).
Is it safe to manually generate/edit these .appxsym and .appxupload for publishing?
Yes. This is fine. As you note, the appxupload's format is documented as being a zip archive containing the .appx and .appxsym files, and the .appxsym file is a compressed file with the app's public symbols. The appx and its creation is documented in App packages and deployment
Generating this yourself or generating it through VS will give essentially identical results, barring differences in the appxupload's contents (most likely different appx options or processing).
来源：https://stackoverflow.com/questions/23687542/is-it-safe-to-manually-generate-appxsym-and-appxupload-for-windows-store-apps