20x138B Material Inside Projectile - What is it?

I saw this German 20mm recently on an auction site (sold, not to me). What is the red waffle pattern material inside the projectile? Is it HE?

German 20mm HE 08

German 20mm HE 01

Other pics if they might help with ID (and just for interest):
German 20mm HE 02

German 20mm HE 03

German 20mm HE 04

German 20mm HE 05

German 20mm HE 09
Source: gunbroker

What you see there is the tracer compound and the waffle shape is to increase the surface so ignition will be safer.

The load is a HEI-T-SD.

Thanks Alex, what I did not notice is the photos show the back of the projectile, not the front with the fuze removed. Interesting that the seller would not show the empty(?) inside.