file_usage.id is type varchar_ascii but its default 0 is PHP type integer

In core/modules/file/file.install the schema for the file_usage declares the ID field as 'varchar_ascii', but sets the default value to the number 0. If the default value should be either the string '0' or '' (empty string).

function file_schema() {
  $schema['file_usage'] = [
    'fields' => [
      ...
      'id' => [
        'description' => 'The primary key of the object using the file.',
        'type' => 'varchar_ascii',
        'length' => 64,
        'not null' => TRUE,
        'default' => 0,
      ],
      ...
    ],
  ];
}