Adds a favicon link to the document head section.
The site root directory is the best place for the favicon file.
Some older browsers and most feed readers have no way of specifying the favicon file location in the document or feed markup. They always attempt to retrieve it from the site's root directory.
Most browsers look up the favicon file in the default location automatically, but some do not. They need to be told where it is located and this is what this plugin does.
Up to you. Choose whatever way is easiest for you.
If you edit the theme's
header.php you will need to make the same
changes again if you later on update or change your theme. With this plugin
you do not need to remember to do that and upgrading becomes simple.
In this case you probably do not need this plugin. It might be still
best to put the
favicon.ico file in your site's root directory.
This is well documented elsewhere. A good place to start is to understand Wikipedia article on favicon.