Which of the following is not a requirement for submitting a theme to the Shopify theme store?

The reason the selection indicating that the theme must include social buttons for all major platforms is not a requirement for submitting a theme to the Shopify theme store is because Shopify does not mandate the inclusion of social media buttons as part of theme submission criteria. While integrating social buttons can enhance a store's functionality and user experience, it is not a strict requirement to ensure that the theme meets Shopify’s guidelines.

The other requirements highlight important aspects that ensure themes provide a good user experience and technical soundness. A responsive layout is essential for usability across different devices, which is a fundamental aspect of modern web design. Using protocol-independent URLs for assets ensures that themes function correctly regardless of whether a site is accessed via HTTP or HTTPS, promoting security and compatibility. Supporting variant images is crucial for eCommerce, as it allows for displaying different images for product variations, enhancing the customer's shopping experience.