Manufacturer ID "EXT" on grenade GR POL EXPL MDF1

I was forwarded this image with permission to publish here.

It is the fuze of a French designed GR POL EXPL MDF1 grenade (hand or rifle).
Design was by Losfeld and Luchaire got tasked with manufacture of these.

The manufacturer given here is “EXT” (dated 1991) which I can not find in any of my lists (merely a Swiss cheese in paper format).

Is anybody able to positively ID the manufacturer “EXT”?

For reference the complete item and background in French: