Interpret point cloud data

I just received point cloud data from the astra mini s an this are the min/max values:
xMin: -789.5155, xMax: 543.00037
yMin: 0.0, yMax: 675.9223
zMin: 0.0, zMax: 1613.0

I have no idea how to interpret this data, are these millimeters? Why does x have negative values?