WordPress at a glance
filter is not described

rss_update_period filter-hook . WP 2.1.0

Filters how often to update the RSS feed.

Usage

add_filter( 'rss_update_period', 'filter_function_name_8756' );
function filter_function_name_8756( $duration ){
	// filter...

	return $duration;
}
$duration(string)
The update period. Accepts 'hourly', 'daily', 'weekly', 'monthly', 'yearly'.
Default: 'hourly'

Where the hook is called

In file: /wp-includes/feed-rss2.php
rss_update_period
wp-includes/feed-rss2.php 61
echo apply_filters( 'rss_update_period', $duration );
wp-includes/feed-rdf.php 42
echo apply_filters( 'rss_update_period', 'hourly' );
wp-includes/feed-rss2-comments.php 56
echo apply_filters( 'rss_update_period', 'hourly' );

Where the hook is used (in WP core)

Does not used.