Invalid mas build?

I'm running a version of cordova-electron forked from 1.1.1, with the only change being that Electron is updated to 6.1.7 [as you can see here](https://github.com/buu700/cordova-electron-tmp/compare/ab2d76c6e9a78e468e720fa336329782a37d3f92...master). As far as I can tell based on the output below, this works as intended.

However, my package is being rejected by the Mac App Store: https://github.com/electron/electron/issues/20027#issuecomment-585545947. The replies from the Electron maintainers suggest that this is likely an issue with cordova-electron:

> dirty build with dmg in it . . . I'm saying you didn't use the `mas` build. Whatever tooling you are using is not using the `mas` build of Electron as that symbol list is basically a history lesson in all the symbols we've removed in the past.

Any ideas?

---

```
[Cordova Electron] The built package size may be larger than necessary. Please run with --verbose for more details.
• electron-builder version=22.3.2 os=19.2.0
• writing effective config file=platforms/electron/build/builder-effective-config.yaml
• installing production dependencies platform=darwin arch=x64 appDir=/Users/buu700/cyph/cyph-phonegap-build/platforms/electron/www
• packaging platform=darwin arch=x64 electron=6.1.7 appOutDir=platforms/electron/build/mac
• packaging platform=mas arch=x64 electron=6.1.7 appOutDir=platforms/electron/build/mas
• building target=DMG arch=x64 file=platforms/electron/build/Cyph-1.0.42.dmg
• signing file=platforms/electron/build/mas/Cyph.app identityName=3rd Party Mac Developer Application: Cyph, Inc. (SXZZ8WLPV2) identityHash=C8AE49EA521129CB8F6E7EFC648A04CC9385C411 provisioningProfile=/Users/buu700/.cyph/nativereleasesigning/apple/macOS_Distribution.provisionprofile
• building block map blockMapFile=platforms/electron/build/Cyph-1.0.42.dmg.blockmap
```

Start with the electron-builder 22.3.2 output and the generated builder-effective-config.yaml, then compare the darwin and mas packaging entries for Electron 6.1.7. Review the linked Electron issue and the fork comparison for relevant build changes. Done means producing a Mac App Store package that is accepted without the reported invalid-build rejection.

Written by the indexing model from the issue text.