How did you get that idea?

This is what an Electron app looks like:

  $ ls Atom.app/Contents/Frameworks
  Electron Framework.framework
  other stuff...

You might also find a bunch of js files lying around:

  $ find Atom.app -name *.js
  Atom.app/Contents/Resources/app/apm/node_modules/chainsaw/index.js
  Atom.app/Contents/Resources/app/apm/node_modules/fs-constants/index.js
  Atom.app/Contents/Resources/app/apm/node_modules/fs-constants/browser.js
  very long list...

Whereas these are the frameworks Zoom ships with:

  $ ls zoom.us.app/Contents/Frameworks/
  CptHost.app              asproxy.framework        nydus.framework          zMacRes.bundle
  Scintilla.framework      caphost.app              protobuf.framework       zMacResRetina.bundle
  Transcode.app            cmmlib.framework         ssb_sdk.bundle           zSIPCallUI.bundle
  ZCommonUI.framework      curl64.framework         tp.framework             zSIPSDK.bundle
  ZMScreenshot.app         faac.bundle              util.framework           zSipCallApp.bundle
  ZoomPhone.app            libcrypto.1.0.0.dylib    viper.framework          zVideoApp.bundle
  ZoomUninstaller.app      libmpg123_mac.bundle     xmpp_framework.framework zVideoUI.bundle
  airhost.app              libssl.1.0.0.dylib       zAutoUpdate.bundle       zWebService.bundle
  annoter.bundle           libz.dylib               zChatApp.bundle          zlt.bundle
  aomagent.bundle          mcm.bundle               zChatUI.bundle           zmLoader.bundle
  aomhost.app              mphost.app               zData.bundle             zmb.bundle

Instead of Javascript files there are tons of Interface Builder files in the bundle:

  $ find zoom.us.app -name *.nib
  zoom.us.app/Contents/Resources/en.lproj/MainMenu.nib
  zoom.us.app/Contents/Frameworks/zChatUI.bundle/Contents/Resources/ZMSettingRecordingViewController.nib
  zoom.us.app/Contents/Frameworks/zChatUI.bundle/Contents/Resources/ZMChatsSearchField.nib
  zoom.us.app/Contents/Frameworks/zChatUI.bundle/Contents/Resources/loadingInfoView.nib
  zoom.us.app/Contents/Frameworks/zChatUI.bundle/Contents/Resources/ZMDiagnosticViewController.nib
  ...

A Linux job opening: https://zoom.wd5.myworkdayjobs.com/en-US/Zoom/job/Phoenix-AZ...

  - 5 years of C/C++ programming experience.
  - 3 years of experience in Linux native application development.
  - Having experience in QT development is preferred.

Mac OS job opening: https://zoom.wd5.myworkdayjobs.com/en-US/Zoom/job/Phoenix-AZ...

  - 2 years of experience in MacOS native client development.
  - Proficient in C++, Xcode, Objective-C and Cocoa Framework.