If you cannot open an Excel file and see Excel cannot open the file because the file format or extension is not valid error, see this post.

What is HAR file? Har or HTTP Archive Format file is a JSON format that is used to analyze and detect bugs during an HTTP session.

Ubuntu is a free computer system, like Windows or macOS, but it’s built by a community. It’s great for programmers because it’s very flexible and has lots of tools already built-in that help you code.