[Bug]: CORS on private network ( fetch to localhost url fails due to CORS ) #36445

Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

Electron Version

21.3.0

What operating system are you using?

macOS

Operating System Version

macOS M1 Monterey 12.6

What arch are you using?

arm64 (including Apple Silicon)

Last Known Working Electron version

19.0.13

Expected Behavior

From a website served via https, an javascript fetch to http://localhost:8080 call should be successful.

Actual Behavior

Unable to access localhost URLs(http://localhost:8080) from a website(https://example.com)
Despite turning off websecurity, allowing insecure content.

Testcase Gist URL

https://gist.github.com/dheerajkysetti/ae620986fcdd68e18d1d713cc05b0a4a

Additional Information

The http://localhost URL call should be successful from a website served over https
or have an flag/switch to enable disable it
or have intercepts via which such an access can be controlled programatically.
Adding headers(Access-Control-Allow-Private-Network:true) in onBeforeHeadersReceived