What about possibility of making JEI schematics like ExtraUtilities2 do. Something like
mods.jei.JEI.addSchematic(IItemStack, IBlock[[[]]]);

I've found out that it's related to ExtraUtils2, not JEI itself. That's some structure render, demonstrating how to use smth:

(It's rotating!)

Yea unfortunately I can't add support for something like that.

We have a template.

Also what is a Jei schematic?

I would think he's talking about a ExtUtils2 specific JEI handler.
https://github.com/rwtema/Extra-Utilities-2-Source/blob/master/1.10.2/src/main/java/com/rwtema/extrautils2/crafting/jei/BlockPatternHandler.java

Maybe that one?