blog_view in modules/blog/blog.module
Implementation of hook_view().
comment_reply in modules/comment/comment.pages.inc
This function is responsible for generating a comment reply form. There are several cases that have to be handled, including:
drupal_get_breadcrumb in includes/common.inc
Get the breadcrumb trail for the current page.
hook_view in developer/hooks/node.php
Display a node.
template_preprocess_forums in modules/forum/forum.module
Process variables for forums.tpl.php