Since the Browse tab is pretty much the first thing you see on a SharePoint 2010 page, you will probably want to edit it.
Although it appears as a ribbon tab, it’s not. So you don't have to deal with features and custom actions in order to edit it. it’s much simpler:
Just open your master page. Find the div element who’s id is “s4-titlerow”. This is your Browse tab (You can clearly see that it’s not part of the ribbon, but part of the body of the document).
you can edit the inner content of the div as you want, but it’s recommended to leave the div itself intact since SharePoint’s new positioning and scrolling system is using these ids.