The Kfir is a design improvement over the Mirage figters in that is is optimized more of an attach rather than a supersonic interceptor. To that end, there is a leading edge extension to improve low speed performance ( and some high speed drag improvement ). Since it is added to the outer wing, it is called a Dog tooth extension.
https://en.wikipedia.org/wiki/Leading-edge_extension
Anyhow, for this model, it is a simple fold over part
and glued in place.
Simple and easy.
Isaac