Start from Python 3.6.3, the offical chm document is full of corrputed character.

Example: the first page which is `What’s New In Python 3.6` `’`is `0x92` in cp1252 and will not display correctly in non western european code page.  An another example is `9.1. numbers — Numeric abstract base classes` `—` is `0x97`.

The Microsoft HTML Help does not recognise `<meta http-equiv="Content-Type" content="text/html; charset=cp1252" />`.

Then, how to solve it?

According to this https://blogs.msdn.microsoft.com/sandcastle/2007/09/29/chm-localization-and-unicode-issues-dbcsfix-exe/

I recommand to use the following command to make the hhc encoding chm as cp1252:

SbAppLocale.exe $(LCID) "%PROGRAMFILES%\HTML Help Workshop\hhc.exe" Path\Project.HHp

I donnot know to how to submit patch and it seems quite easy to fix by offical windows developer.