Header Insert For All Pages: meta name items such as: keywords/robots link to an additional css style file <script> items such as: ebay (epn-smart-tools.js), Google Analytics Global site tag (gtag/js), Google Custom Search Engine (cse.js), Google Adsense Page Level Ads
Header Insert When Not Displaying a Topic: meta name items such as: description
Default Header: This is your general website/forum header for when "Unique Header/Footer" is not enabled in your advanced per-forum "Custom Inserts" settings page. this is also a good place to include the code for manually inserting "adsbygoogle.js" <script> responsive banner ad items, just below your page header layout html.
Default Footer: This is your general website/forum footer for when "Unique Header/Footer" is not enabled in your advanced per-forum "Custom Inserts" settings page. this is also a good place to include the code for manually inserting "adsbygoogle.js" <script> responsive banner ad items, just above your page footer layout html.
Attached Screenshot of Control Panel > General > HTML Includes page with sample descriptions
