WordPress at a glance
filter is not described

get_avatar_data filter-hook . WP 4.2.0

Filters the avatar data.

Usage

add_filter( 'get_avatar_data', 'filter_function_name_7225', 10, 2 );
function filter_function_name_7225( $args, $id_or_email ){
	// filter...

	return $args;
}
$args(array)
Arguments passed to get_avatar_data(), after processing.
$id_or_email(mixed)
The Gravatar to retrieve. Accepts a user_id, gravatar md5 hash, user email, WP_User object, WP_Post object, or WP_Comment object.

Where the hook is called

get_avatar_data()
wp-includes/link-template.php 3983
return apply_filters( 'get_avatar_data', $args, $id_or_email );
wp-includes/link-template.php 3877
return apply_filters( 'get_avatar_data', $args, $id_or_email );
wp-includes/link-template.php 3916
return apply_filters( 'get_avatar_data', $args, $id_or_email );

Where the hook is used (in WP core)

Does not used.