Metamask-extension: Not sure why `window.ethereum` is not injected in html files opened locally (directly from os files without a web server).

[Muhammad-Altabba]

Describe the bug
Not sure why window.ethereum is not injected in html files opened locally (directly from os files without a web server).

Is this intended for security reason? Or is this a bug?

To Reproduce
Steps to reproduce the behavior:

If I open an HTML page from my OS (by double click on it), ethereum is undefined. I also tried this by both: writing javascript blocks inside the HTML page, and from browser console.

Expected behavior
ethereum is defined in both ways: if the page is opened locally, or hosted on a web server.

Browser details:

• OS: Both Windows 10 and Ubuntu 18
• Browser: Chrome
• MetaMask: Version 6.0.1

[jamesmorgan]

see: https://github.com/MetaMask/faq/blob/master/DEVELOPERS.md#globe_with_meridians-https---web-server-required

Due to browser security restrictions, we can't communicate with dapps running on file://. Please use a local server for development.

I think its because of this.

[Muhammad-Altabba]

So it is because of browser security restrictions.
Many thanks,