Answer:
Developer tools.
Explanation:
The main aim of developer tools to loading the HTML(hypertext markup language), CSS and JavaScript it describes how much time takes the page to load in the web browser.
The developer tools make the task easier for the designer to locate the source code which is applied to a specific page element.We can easily see the source code of the particular website by using the Developer tools. So it makes the task easier for programmers and developers.