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filter is not described

get_terms_fields filter-hook . WP 2.8.0

Filters the fields to select in the terms query.

Field lists modified using this filter will only modify the term fields returned by the function when the $fields parameter set to 'count' or 'all'. In all other cases, the term fields in the results array will be determined by the $fields parameter alone.

Use of this filter can result in unpredictable behavior, and is not recommended.

Usage

add_filter( 'get_terms_fields', 'filter_function_name_1113', 10, 3 );
function filter_function_name_1113( $selects, $args, $taxonomies ){
	// filter...

	return $selects;
}
$selects(array)
An array of fields to select for the terms query.
$args(array)
An array of term query arguments.
$taxonomies(array)
An array of taxonomies.

Where the hook is called

WP_Term_Query::get_terms()
wp-includes/class-wp-term-query.php 628
$fields = implode( ', ', apply_filters( 'get_terms_fields', $selects, $args, $taxonomies ) );

Where the hook is used (in WP core)

Does not used.