Re: HEAD
I think the "HEAD" is coming from the History.markdown file. It is strange that the "HEAD" does not show up in a local jekyll serve development environment. I suspect the code below is picking up History.markdown in jekyll, along with about.md when rendering header.html.
https://github.com/rjraya/rjraya.github.io/blob/ddc6a2f5c5804961da6ac79472b7f77052bef267/_includes/header.html#L20-L27
<div class="trigger">
{%- for path in page_paths -%}
{%- assign my_page = site.pages | where: "path", path | first -%}
{%- if my_page.title -%}
<a class="page-link" href="{{ my_page.url | relative_url }}">{{ my_page.title | escape }}</a>
{%- endif -%}
{%- endfor -%}
</div>
RE: Page Title URL Computational reflections
Change the href from / to /blog in this line
https://github.com/rjraya/rjraya.github.io/blob/ddc6a2f5c5804961da6ac79472b7f77052bef267/_includes/header.html#L7
<a class="site-title" rel="author" href="{{ "/blog" | relative_url }}">{{ site.title | escape }}</a>
RE: About URL
Remove the permalink : /about/ from the about.md page. The about.md will be come the homepage (e.g. /) in the next step.
https://github.com/rjraya/rjraya.github.io/blob/gh-pages/about.md
RE: Show about.md information on homepage rjraya.github.io and show _posts markdown files under rjraya.github.io/blog
Let jekyll use the default behavior of assigning permalinks based on the markdown filename.
Rename index.md to blog.md. This will move the list of _posts files from / to /blog.
Rename about.md to index.md. This will move the content of about.md from /about to /.