WordPress at a glance
filter is not described

thread_comments_depth_max filter-hook . WP 2.7.0.

Filters the maximum depth of threaded/nested comments.

Usage

add_filter( 'thread_comments_depth_max', 'filter_function_name_8419' );
function filter_function_name_8419( $max_depth ){
	// filter...

	return $max_depth;
}
$max_depth(int)
The maximum depth of threaded comments.
Default: 10

Where the hook is called

In file: /wp-admin/options-discussion.php
thread_comments_depth_max
wp-admin/options-discussion.php 97
$maxdeep = (int) apply_filters( 'thread_comments_depth_max', 10 );

Where the hook is used (in WP core)

Does not used.