Add user email and username under the "View" tab at /user/%
You can always create a block through Views and display this information. Here's how to do that:


Create a new view, choose to show "Users" and create only a block.
Add "E-mail" field.
Add "Contextual filter" for the "User: Uid" field.
For filter configuration choose "Provide default value" and then "User ID from URL".
Show the block in content area, and configure it so it's displayed only on specific pages. Enter the aliased path you use for user profiles. For example: profile/*. This is necessary because the system URL for user profile pages is user/[uid], which you cannot distinguish from user/login, user/register and so on.


Do note that this will make the username/email available to everyone who has the permission to view user profiles.

Hope this helps.