UX30 package in ZIP format, 3.00 MB, the larger companion to the unlocked firmware entry for the same model. The name states only the model, so check whether it holds schematics, boardview data or stock firmware after extraction. Any standard unzip tool will open it. Schematic content is used to follow power rails and signals, while boardview files need a viewer such as OpenBoardView. Confirm the board number and revision on the PCB, and back up the flash chip before writing any image.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @IT_SERVICE_WORLD. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.