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filter is not described

(context)_memory_limit filter-hook . WP 4.6.0

Filters the memory limit allocated for arbitrary contexts.

The dynamic portion of the hook name, $context, refers to an arbitrary context passed on calling the function. This allows for plugins to define their own contexts for raising the memory limit.

Usage

add_filter( '(context)_memory_limit', 'filter_function_name_2604' );
function filter_function_name_2604( $filtered_limit ){
	// filter...

	return $filtered_limit;
}
$filtered_limit(int/string)
Maximum memory limit to allocate for images. or the original php.ini memory_limit, whichever is higher. Accepts an integer (bytes), or a shorthand string notation, such as '256M'.
Default: '256M'

Where the hook is called

wp_raise_memory_limit()
wp-includes/functions.php 5728
$filtered_limit = apply_filters( "{$context}_memory_limit", $filtered_limit );

Where the hook is used (in WP core)

Does not used.