WordPress at a glance
filter is not described

site_search_columns filter-hook . WP 4.6.0

Filters the columns to search in a WP_Site_Query search.

The default columns include 'domain' and 'path.

Usage

add_filter( 'site_search_columns', 'filter_function_name_1188', 10, 3 );
function filter_function_name_1188( $search_columns, $search, $this ){
	// filter...

	return $search_columns;
}
$search_columns(array)
Array of column names to be searched.
$search(string)
Text being searched.
$this(WP_Site_Query)
The current WP_Site_Query instance.

Where the hook is called

WP_Site_Query::get_site_ids()
wp-includes/class-wp-site-query.php 514
$search_columns = apply_filters( 'site_search_columns', $search_columns, $this->query_vars['search'], $this );

Where the hook is used (in WP core)

Does not used.