1)A username must be 3 or more characters, and not contain two periods: ".." or a forward or backslash "" "/" or "%" sign. All other UTF-8 are allowed.
2)The user profile will be at https://flake.art/{username}
3) This will have oembed for the username: https://oembed.com/#section1
4) Clicking on a username link will load the userpage and keep the url https://flaek.art/{username} The app should be navigable with URLs.
5) user profile will list all NFTs owned by the user that they want to share.
6) User profile pages can be hidden by the backend if the user chooses.
Make sure it passes the share debugger:
https://developers.facebook.com/tools/debug/