It means that no matter if you win or not, any material submitted will be theirs, if I understood it correctly.
Thanks @Robert ! However , I don’t think ! The condition is only for the prize winners … but even in this case it seems the developer still has some IP rights … what do you think about that ? Is there a Google official here who can answer us ?
Yep, you retain the IP rights but if you read below, it also says that they can do whatever they want with it… As you, I am not sure how those apparently clashing statements work, but I bet it’s (quite obviously) to their advantage. I might be wrong anyway since I am not a lawyer. Try to paste it in some good A.I. and ask the a.i. to clarify it 
I re-read it and I was wrong… if you WIN then you do have your IP rights but you grant also any conceivable right to google including derivative works (so if they modify it even a bit, the product is theirs and I have no idea in that case what would mean that you retain the rights)
The key phrase is:
As between Sponsor and You, You retain ownership of all intellectual and industrial property rights (including moral rights) in and to the information, in connection with Your Submission. As a condition of receiving the Prize, each Confirmed Winner grants Google, its parent, affiliates, agents, and partner companies, a perpetual, irrevocable, worldwide, royalty-free, and non-exclusive license to use, translate, dub, broadcast, exploit, reproduce, adapt, modify, rearrange, add to, delete from, copy, publish, distribute....
Thank you Robert ! You’re a legend 