the idea is good but the implementation is questionable, in the same way I can find the “deconstruction plan” and mark it as a filter, I don’t know how to do this better, or add a button to the interface that will set this item as a filter or add keyboard shortcuts

Dial-up, I can't understand what you mean. Please could you explain more clearly?

ok, it seems that either I incorrectly described what I want or Google translator translated something wrong.
for starters, I don’t quite understand what the point of adding an item is, and why I should install the mod at all, because I can choose a deconstruction plan (in some blueprints I saw the use of fish) as a non-existent item (because who in their right mind would put blueprints on the conveyor )
another reason is that if I play on a heavy build I will need time to find it (your null item) in the filter menu
Therefore, if this mod was created with the goal of setting up a splitter for only 1 output, then it makes more sense to add quick access to setting such a filter, as I wrote above, you can try adding keyboard shortcuts, when pressed, which will set a null item filter on the hovered splitter, or add a button that will do the same thing but from the splitter gui.

Ah yes, now I understand. You've made a good point. Thanks for clarifying your post.

Thank you for your feedback. This mod -- and its implementation as an item -- is inspired by the similar feature from IR3, which I found useful and wanted a standalone version of. It is entirely possible to achieve the same effect using a deconstruction planner or similar as a filter in a splitter; the purpose of this mod is to provide a more explicit symbol on the splitter in alt mode.

Adding an interface button or keyboard shortcuts or both are all good ideas. If they were to be implemented, however, the design would also have to account for the left/right sides of splitters. That complexity is beyond the scope of this very simple mod.

I have updated the mod description to make the purpose clearer.

ok, if someone doesn't do it before I finish my mod then this will be a great idea for the next one