The ISO is split into to files because github cannot handle files larger than 2 GB.

1. Download the .iso.z01 and the .iso.zip
2. Then combine them with cat [manjaro-mate].iso.z01 [manjaro-mate].iso.zip > manjaro-mate.zip
3. Now you simply have to unzip the file with unzip manjaro-mate.zip
4. Done now you have the ISO

Corresponding profile: https://github.com/FreaxMATE/iso-profiles