Base TWRP tree generated from TWRP device tree generator with a lot of manual tweeking added. The filesystem layout is left untouched.
The Travis file is very distantly inspired by rokibhasansagar's. For now it's relying on the minimal TWRP manifest for Android 11 over there. Even at a depth of 1 it's a humoungous tree to pull.
The ROM version used to extract a base recovery img from is RMX3085export_11_A.19_2021081120010000.
It's not guaranted to produce a functional TWRP recovery image at this point.