Puntuado con 5 de 5 estrellas

por Firefox user 22ae43 el Nov. 2, 2018 · enlace permanente

It *does* work for sortiing accounts but you have to manually install the latest pre release ie. 1.2.0pre3 as per one of the other reviews.
https://github.com/Ximi1970/Manually-Sort-Folders/releases/download/v1.2.0pre3/manually_sort_folders-1.2.0pre3.xpi