You can use Pads, a Pcb layout software from Mentor graphics: https://www.pads.com/ for board files (.brd)
All schematics are in Pdf format, thus you can use any capable Pdf reading software, Adobe reader on Windows, Apple has built in system software.
Problem is besides Zxw you won't find anyone able to supply reliable schematics and board files..manufacturers have no interest in publishing them and employees have no interest in getting fired and sued by their principals for leaking industrial secrets. You 'll find some older partially reliable files here and there around the net, good enough to get an idea on how things work, but not enough to keep up with professional needs.