Mick!
TreeHouser
If you go back to page 321 where I posted it in 2021, it has 2 ‘pages’ (swipe left) second one shows the fell from behind, the jack, the intended lay and all that.I think what you(and me) are seeing as a hinge isn't anything. It's just some ragged wood casting shadows. I think the real hinge is 90° from the apparent hinge. Mick said the white thing is a jack handle. I'll have to take his word for it, but if you squint, it does kind of look like there's a pocket there for a jack.