After hours of jumping around, my findings are as such:
Area below the first chest in raid, the small leafy passage way, connects to the larger area accessed from over the top of the cliffs in the templar area, in both the light rocky zone and the vec mechinery sections, from top to bottom there are no useful passageways or hidden areas, there is however a small passageway close to the enterance of the vex machinery area (entering from under the first chest side), that leads to a little window overlooking part of the cave you ascend when heading towards the templar, despite being a fenced window a few knee slides can push you through it, though to no real benefit.
There are a number of golden gated pieces around the areas but none of them would seemingly bring you anywhere useful.
It seems, to me at least, that at some point or another, "The Trial of Kabr" was meant to be a puzzle based area (no spawn holes around the area), if you glitch through the main door in non-raid mode, the entrance to the cave system that takes you down to the templar is closed off, preventing you from going deeper than the first chest, so I feel as though their plan was to close off this area in Hard mode, and have people navigate through the jumpy-puzzle hot mess that is "The Trial of Kabr", which would then bring them out in the templar area to continue onwards.
It does seem strange that as the raid currently stands, the trial of kabr section serves as nothing but a chest spawn and an extremely short passageway to the templar. Another potential outcome, could have been that the area that this place is in, contained a small boss, or further vanishing steps which would eventually give you access to the later jumping area.
All in all the area that connects the templar boss arena and the trial of kabr load zone has nothing of notable value at current, it may be used at a later date, it may remain unused and abandoned, was still fun exploring it.