Why do some pages don't have titles in the deployed site?

Consider the following pages in https://git.github.io/ :

• https://git.github.io/Hacking-Git/
• https://git.github.io/General-Microproject-Information/

Observe that even though they have a proper title mentioned in the corresponding Markdown files, the titles don't appear in the body of the text. It is only visible in the link and the title of the tab in the browser. Is there a particular reason for this? Or is there no particular reason for this?

将对应的 Markdown 文件与已部署的 Hacking-Git 和 General-Microproject-Information 页面进行比较，然后追踪它们的标题是如何渲染的。确认缺失的正文标题是否是有意为之，或找出阻止它们显示的网站行为；当该行为得到解释，或两个页面都一致地显示其标题时，即视为完成。