This plugin sets the <title>
tag in the <head>
section of the HTML output.
First page / index page:
title = name of the website | subtitle (short description of the website)
All other posts and pages:
title = title of the post/page | name of the website
Notes:
The code is a very basic copy of:
https://codex.wordpress.org/Plugin_API/Filter_Reference/wp_title