All of these events are for the Manage subscriptions page in the UCP. They're designed to allow us to add the concept of per-topic and per-forum notification settings (i.e. for this topic I want to be notified by email and board notification, but for this topic I only want board notifications and not emails).

Identifier: core.ucp_subscribed_post_data
Location: includes/ucp_main.php, line ~215 (before $unwatch handling)
Parameters:
$post_data - the $_POST data from the submitted form, if any.
Explanation: This would allow us to intercept additional variables we add to the form and perform some form handling if necessary.

Identifier: core.ucp_main_subscribed_forums_modify_query
Location: includes/ucp_main.php, line ~301 (just before the execution of the query to grab subscribed forums)
Parameters:
$sql_ary - the array containing the SQL parameters for the subscribed forums query
Explanation: This would allow us to modify the query to get subscribed forums.

Identifier: core.ucp_main_subscribed_forum_modify_template_vars
Location: includes/ucp_main.php, line ~363 (after building the template variables array)
Parameters:
template_vars - Array containing the template variables for the row
row - Array containing the subscribed forum row data
forum_id - Forum ID
folder_image - Folder image
folder_alt - Alt text for the folder image
unread_forum - Whether the forum has unread content or not
last_post_time - The time of the most recent post, expressed as a formatted date string
last_post_url - The URL of the most recent post in the forum
Explanation: This would allow us to incorporate the additional data from the previous hook into the template variables for each subscribed forum.

Identifier: core.ucp_main_topiclist_count_modify_query
Location: includes/ucp_main.php, line ~666 (just before the query to get the topic count)
Parameters:
sql_array - The subscribed/bookmarked topics query
forbidden_forum_ary - The list of forbidden forums
user - The current user
mode - The type of topic list ('subscribed' or 'bookmarks')
Explanation: This allows us to modify the query to get the number of subscribed/bookmarked topics. Mostly to ensure this matches up with any modifications we make to the query to get the list of topics in the hook below.

Identifier: core.ucp_main_topiclist_modify_query
Location: includes/ucp_main.php, line ~734 (just before the query to get the list of topics)
Parameters:
sql_array - The subscribed/bookmarked topics query
forbidden_forum_ary - The list of forbidden forums
user - The current user
mode - The type of topic list ('subscribed' or 'bookmarks')
Explanation: This allows us to modify the query for the list of subscribed/bookmarked topics so we can pull in additional data.

Identifier: core.ucp_main_topiclist_topic_modify_template_vars
Location: includes/ucp_main.php, line ~842 (after the template variables array for each topic is built)
Parameters:
template_vars - Array containing the template variables for the row
row - Array containing the subscribed/bookmarked topic row data
forum_id - ID of the forum containing the topic
topic_id - Topic ID
replies - Number of replies in the topic
topic_type - Topic type
folder_img - Folder image
folder_alt - Alt text for the folder image
icons - Array containing topic icons
unread_topic - Whether the topic has unread content or not
view_topic_url - The URL of the topic
Explanation: This will allow us to take the additional data from modifying the topic query earlier and add it to the template variables for each topic row.