Gmail Browser is a standalone browser for the Gmail website. The application allows you to check your e-mail on your desktop without having to open a web browser to do it. The reason why the developer created this app was because he often found himself distracted by having Gmail opened next to other websites or by being able to easily open a new tab and browse. Thus, he figured he wouldn't be so distracted if Gmail was a standalone app.
Gmail Browser lets you open Gmail and other Google apps on your desktop. The application loaded my Gmail account well enough, although some features like chat didn't work. I was able to see my mails, search for mails using the search field and even access my Google Documents. It was as fast as the web version and it showed new e-mails instantly. One feature that this app is missing is notifications. Those are a very important part of my workflow and I can't do without them.
In the preferences window, you can change the web address that is opened when you launch Gmail Browser and activate an ad blocker.
Gmail Browser is free but it doesn't seem like it has been updated in a few years.