Which file provides site structure details in a headless Sitecore setup?

The file that provides site structure details in a headless Sitecore setup is indeed sitecore.json. In a headless architecture, Sitecore leverages JSON format to represent the site’s structure, including important elements such as items, layouts, and rendering configurations. This format makes it easier for frontend applications to consume Sitecore content via APIs, enhancing the flexibility and efficiency of content delivery.

In contrast, sitecore.xml traditionally supports the configuration of Sitecore's various components in older, more monolithic setups. The web.config file is crucial for ASP.NET applications, as it defines application-level settings such as security and database connections, but it does not specifically outline the content structure of a Sitecore site. Similarly, connectionStrings.config focuses solely on database connection string settings, which are essential for the application's database connectivity but do not provide any information about the site's content model or structure. Thus, sitecore.json plays a pivotal role in representing site structure in a modern, headless Sitecore environment.