app/overrides/add_favorite_variants_to_product_tab.rb
Deface::Override.new(
virtual_path: 'spree/admin/shared/sub_menu/_product',
name: 'add_favorite_variants_to_product_tab',
insert_bottom: "#sidebar-product",
text: %Q{ <%= tab :favorite_variants %> },
sequence: { after: 'select_products_tab' }
)