Term meta arrived in 4.4 and nobody noticed

Attaching data to a category or tag used to mean an option keyed by term id, a separate table, or a plugin. 4.4 added a real meta table for terms with the same API shape as post meta, and a great deal of code has not caught up.

add_term_meta( $term_id, 'brand_logo_id', $attachment_id, true );
get_term_meta( $term_id, 'brand_logo_id', true );

$terms = get_terms( array(
    'taxonomy'   => 'brand',
    'meta_query' => array(
        array( 'key' => 'featured', 'value' => '1' ),
    ),
) );

The upgrade routine that creates the table runs on the database version bump, so a site restored from an old dump can be on 4.4 without having it — get_term_meta() then returns empty rather than erroring, which is a confusing way to find out. The meta query support in get_terms() is the part that makes it genuinely useful.