On default Debian KED installation, the Chinese characters on some websites, e.g. www.baidu.com, are not properly displayed. With the font inspector in Chromium, I can see that some Japanese fonts are selected for them. I suspect that the website doesn’t specify a proper fall back Chinese font if the top choice is unavailable. Since Google Noto fonts are installed by default on most platforms, I could have set them as the fallback, so edit the proper file as shown below, and the issue goes away.
# in ~/.config/fontconfig/fonts.conf