By "former berm" I mean the protective walls built up to 1987, with the exception of smaller extensions (e.g. at Guerguerat 2021), in the gradual pushback of the areas under Polisario/separatist influence by the Royal Moroccan Armed Forces.
These are not only found in the Boukraa area. See the overview of the walls in:
https://en.wikipedia.org/wiki/Moroccan_Western_Sahara_Wall#/media/File:Western_sahara_walls_moroccan_map-en.svg
in: https://en.wikipedia.org/wiki/Moroccan_Western_Sahara_Wall

If you zoom in, you will see the parts of the historic walls already marked on Open Street Map! Also in the wall system that you overlooked in this case.

Best regards
Tilges