The forward clips, positioned aft of the shrouds could be used to hold a guy. The actual part that is usually sold for that pretty similar in function: closed towards the outside, but guy can be "hooked in" from the inside. Usually, I think, not placed as far inboard, but I can't be sure, because I don't have something like that rigged for my spinnaker. (Use a search engine/browser to search the forum, not the internal search, and you might find something in the older posts).
I've seen pictures of aft blocks that are placed in front of the stern cleats. Often these allow the line to go forward below the deck to some turning block with cleat. I did something simpler that started out as a temporary solution while figuring out whether sailing with a spinnaker was for me. However, adding blocks like these to those clips in the back might work.
Before you use the clips for anything spinnaker-related, make sure that they are strong enough. If you have stern cleats, you might like to copy my setup. I found it does not interfere with using the cleats to tie up. In fact, these work so well, I've stopped thinking about a more "permanent" replacement.
As for the idea that they are for a boom tent, the curious part is that they open inward. However, that might work with a design that incorporates aluminum or fiberglass support that might push outward when installed.
