To hide the default user name appearing in browser tab of view profile page.

Hi,

it's possible to change the page head title string via the Text Editor in Studio (see http://community.lithium.com/t5/Pages-and-layouts/Change-a-page-title/ta-p/72218 for more details).

You can customize that just for the ProfilePage if needed, you can add something like this:

page.head.title@page:ViewProfilePage = {0} User Profile Page {2}

or 

page.head.title@page:ViewProfilePage = User Profile Page

Unfortunately it's not possible to pass additional variables there, so it will not be possible to add the first and last name with this approach. But if you have a title that works for all users, that would be ok.