Test upload to ensure nothing is broken.
Edit - looks like everything is working.
There has been no change in layout upload functionality for a while. Remember to save your question (or edit to your question) before trying to use the code. There is an issue if you get over a certain size, but not many layouts get there.
And after a while, the coupon code times out, so you have to obtain a new one by adding a download.
And sometimes it just hands up, and gotta try again.
Edit 2: see the layout on your other Q&A, so it looks like the upload worked.