Good news, tio540, your images have been released by the PPRuNe gods.
I’m pleased to say that my guess was correct. The images are of the EGT/CHT plots in many EDM manuals.
To the extent that those plots show that EGT and CHT ‘track’ each other always, they are bull****.
CHT ‘tracks’ EGT while mixture is being leaned from rich of peak towards peak. Then something interesting and counter-intuitive happens, approaching and passing peak EGT. From around 25C rich of peak, CHT peaks then starts to decrease as mixture is leaned further. As a consequence, the CHT at peak EGT is lower than CHT is around 25C rich of peak.
As I noted in earlier posts, this outcome is, despite the plots in EDM’s manuals and ironically, observed on every EDM (and other engine monitor) that takes measurements on real engines in the real world.