The global variable Shopify.designMode can be used to detect what?

The global variable Shopify.designMode is specifically designed to identify when the storefront is being viewed in the theme editor. This mode allows developers to test and customize themes without affecting the live storefront that customers interact with. By using this variable, a developer can implement conditional logic in their Liquid templates or JavaScript code that behaves differently when the theme is being edited, facilitating a smoother development and testing process.

The other options do not pertain to the functionality of this variable: it does not provide information about product sales, theme compatibility with mobile devices, or visitor statistics. Therefore, the option reflecting the ability to detect the theme editor's context is the only accurate application of the Shopify.designMode variable.