I need someone to help me understand this wordpress requirements.

I read envato wordpreas requirements but I do not understand the following :

  • Themes must not use features/APIs meant for WordPress core, including these [private functions]

  • Themes must display posts, pages, archive pages, home page, blog page, search, etc., and must support all of the following features:

    • Comments
    • Sidebars
    • Editor style – I do not undrestand this
    • Title tag
  • Themes must be widget-ready in all advertised locations.

    so can anyone explan these points to me with more details please ?