This has been originally reported here:
https://bugs.chromium.org/p/chromium/issues/detail?id=1131397

• Go to http://www.imomoe.in/
• Open DevTools and switch to the Network tab
• Reload the page to make sure to capture all requests
• Select the very first request (the one for the HTML document itself)
• In the sidebar, switch to the "Preview" tab

Expected:
The real page and the previewed response should be exactly the same

Actual:
The previewed response uses a different charset as the real page, so the text content in the preview is different.

Similar problem has been reported here:
Bug 1328203 - Text encoding issues in response preview with Chinese content

But, that bug seems to be related to code-mirror (not using the right charset?)

Honza