HeadNFoot aids in adding Headers and footers to you blog or blog content or insert Http headers into the site.
This allows you to add things such as verification for Google Webmaster Tools to you meta tags, or code for Google Analytics, or even little tweaks to you theme to your site without having to modify your theme.
Not modifying you theme has the advantage that changes will not accidentally be wiped out when you change or upgrade your theme, just go ahead and change your theme and these important changes will still be there.
You can easily add content into the <head> or your page, or just before the end of the content </body>. You can also add content to just before the post/page or post list, and just after too.
If you want to play around with page caching , redirects or what every you need to do with the headers , this is easily accomplished too.