What kind of content ends up in the "System help" block? How could I answer this question myself? I saw the answer to this question and wanted to enable the "System help" block. When I did, I wondered what other content would be showing on my site besides the "Explanation or submission guidelines" field upon node editing.

Via some grep-ing, I found modules/block/block.module and from what I can tell the block is populated from code there. But it isn't clear to me what would end up in that block. What's the correct "Drupal way" of knowing?
Help content, defined in hook_help is added to the "System help" block for display in

system_block_view

via

menu_get_active_help

which returns the valid help content for the current menu path.


  How could I answer this question myself?


You can answer this question yourself by


Studying the Drupal API
Grepping / searching the codebase for relevant text
Asking on Drupal Answers ;)