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filter is not described

rss_update_frequency filter-hook . WP 2.1.0

Filters the RSS update frequency.

Usage

add_filter( 'rss_update_frequency', 'filter_function_name_1916' );
function filter_function_name_1916( $frequency ){
	// filter...

	return $frequency;
}
$frequency(string)
An integer passed as a string representing the frequency of RSS updates within the update period.
Default: '1'

Where the hook is called

In file: /wp-includes/feed-rss2.php
rss_update_frequency
wp-includes/feed-rss2.php 74
echo apply_filters( 'rss_update_frequency', $frequency );
wp-includes/feed-rdf.php 46
echo apply_filters( 'rss_update_frequency', '1' );
wp-includes/feed-rss2-comments.php 60
echo apply_filters( 'rss_update_frequency', '1' );

Where the hook is used (in WP core)

Does not used.