I think they’re testing your submission to make sure it scores (based on test part) above some benchmark. If test scores of your submission are below benchmark, then they may not want to include your model into the mix. I’m a newbie to numerai, so, don’t take it as a fact.
It seems MikeP accepted the suggestion I made, and you upvoted (thanks!), so ‘train’ and ‘validation’ go up to era 1000, and include target numbers. After that, there are still about 27,000 rows of ‘test’ data, currently eras 1001 - 1005, with empty targets.
Next week, era 1001 will become ‘validation’ and have target numbers, era 1006 will become ‘test’. And so forth, each week.