How to access objects transform from modifiers driver?

Hey there guys, I’m pretty new to driver expressions, and it looks like I am missing something obvious. I have a UV Warp modifier which should scale the UV to the object’s scale. As I need to do so about 7000 times because the mesh is instanced by a hair SIM, I realized, that self is pointing to the modifier, now’s the question: how to address the object the modifier is applied to?
Is there a way to point to the object or a workaround in which I don’t have to set all 7000 × 2 drivers?


bpy.data.objects[“mdl_Gras_s1.005”].scale[0] is how far I came, and it seems to be the right direction, but I don’t know how to get the object’s name.

Does anyone have an idea?