What does {{#post}} do?

I have tried to locate this one in the documentation (Sorry Bob – I seem to be somewhat challenged in the layout of the docs).  I saw this code snippet when reading about {{#checkIf}}:

{{#post}}
   {{#checkIf id '==' 10}}
         your code here...
   {{/checkIf}}
{{/post}}

I could not find the {{#Post}} helper anywhere.  I suspect it retrieves properties about the current post, but cannot confirm.  Wondering if anyone knows for sure.

Thanks