HAR files are great for providing additional information about HTTP requests.
These are really useful for debugging difficult issues.
This article will help you creating HAR files and give you a little more information about it.
One of the easiest ways to generate the HAR file is using Google Chrome. You can follow these steps:
Open the page you want to inspect on Google Chrome.
Select the Chrome menu at the top-right of the browser window.
Check the box "Preserve Log" and make sure it is recording the log (red ball on the left).
Refresh the page and navigate, or interact with the page until reproduced the problem you have been experiencing.
On the Network tab, click the right button on the list of requests and select "Save as HAR with content".
Save the HAR file to a convenient place and send this over to support
Firefox
Click on menu on the top right corner and select ‘Web Developer’ from the dropdown.
Once the view changes, click on Network on the next screen.
From here, right click on any area of the network requests and select save all as HAR.
Save the HAR file to a convenient place and send this over to support