The "Feed" tab if active if there is an opened RSS feed. Using this tab you can access the main (title, description, link) and additional fields of the feed.
Feed toolbar
The description of the toolbar and buttons can be found above.
Data input area
This area allows editing any parameters of the RSS feed. It includes three tabs. The “Required Fields” tab contains the obligatory field. The “Optional Fields” are fields that you can either fill or not. The “iTunes Fields” tab is enabled if the iTunes extension support is enabled.
Special Features
WYSIWYG HTML Editor
Feed Editor has a built-in HTML-editor that you can use to edit the “Description” field of the feed. To launch it, click the 
button.
iTunes support
The “Feed” and “Feed Items” tabs have additional tabs that can be used to edit the special iTunes-fields of your feed. They are usually used when creating podcasts. By default, these tabs are disabled. To enable iTunes support in your feed, mark the “iTunes Enabled” checkbox.