What do XHR requests include in the Waterfall analysis view?

The correct option highlights that XHR (XMLHttpRequest) requests encompass details that are captured through W3C resource timings and JavaScript callback execution times. This is significant because the Waterfall analysis view provides a comprehensive overview of how assets, including those requested via XHR, interact and load on a webpage.

When diving into the specifics, this option reveals that the timing of network requests is essential when analyzing performance. By accessing W3C resource timings, users can see the precise moments when a request was initiated, completed, and how long it took to fetch the resource, which in many cases can be crucial for diagnosing performance issues in applications that rely heavily on asynchronous data fetching.

JavaScript callback execution times further enhance this context by showing how long it takes for the page to react or update after the data is received, which is particularly important in understanding user experience and application responsiveness.

In summary, the focus on W3C resource timings and JavaScript callback execution times in the context of XHR requests provides valuable insights into performance, allowing developers and performance analysts to better understand and optimize their applications.