ARIA role attribute value:main
The main element represents the main content of the body of a document or application. The main content area consists of content that is directly related to or expands upon the central topic of a document or central functionality of an application.w3c
The main content area of a document includes content that is unique to that document and excludes content that is repeated across a set of documents such as site navigation links, copyright information, site logos and banners and search forms (unless the document or applications main function is that of a search form).
User agents that support keyboard navigation of content are strongly encouraged to provide a method to navigate to the main element and once navigated to, ensure the next element in the focus order is the first focusable element within the main element. This will provide a simple method for keyboard users to bypass blocks of content such as navigation links.
Authors are advised to use ARIA role="main" attribute on the main element until user agents implement the required role mapping.w3c