What is the use of instrumentation console in lightning experience?

When we are working upon the visualforce pages and are using javascript on the page for different client side validation and processing of records then the console for this becomes a very important part of the development because it helps to see the network hits we make , change static css on the page , debug certain things , check the errors , etc . So instrumentation console is something which helps us to see the time lapsed since last load time , previous page url , session time , etc . Also , to we can record the interactions and download them in JSON format . Please let me know if this was of any help to you.

Hi,

Like we have console, network and other tools in developer tools of a browser where they logs information associated with a web page: network requests, JavaScript, CSS, security errors and warnings. Likewise, Salesforce has created Instrumentation console where we see the interactions- upon clicking anywhere on the page. One can see the Time since loaded, Session start time, Previous Page URL, Sequence, etc.
You can record your interactions and play them again to see the stats, you can download the JSON format of the interaction from right bottom corner icon, you can also load interaction files.
And in the View Waterfall option you can see stats for the transaction and when you play the recorded interaction you can see in different views as chosen in I want to ... dropdown.

Hope this helps.