I can't understand this code
{display property=$theField.id}
This code snippet is from smartjobboard cms file is templates/_system/builder/bf_displaylisting_fieldsblocks.tpl line 91 after parsing it produces this
echo $this->_plugins['function']['display'][0][0]->tpl_display(array('property' => $this->_tpl_vars['theField']['id']), $this);
smart job board uses smarty as template engine.
display
is a smarty plugin function and property
and argument to it. You need to search for something like:
$smarty->registerPlugin("function","display", "... (local function name)");
in their code. Check the manual about plugin functions, and you know what's going on.