I created a seed as I am doing a transfer to a different wallet. When I put the seed of the first password in the light wallet, on the very end, in a bubble are the three letters 'GPW' when I switch wallets and put in the new seed, the letters 'USX' show up in the bubble. What is this?
As stated in this article of Dominik Schiener:
we added a 3 character checksum for seeds. This means that you can now validate if the seed which you have are trying to login with is the correct one. All you need to do is to remember the 3 character checksum and validate upon each login.