Calculating geopotential vs downloading from MARS


On the ERA5 documentation page for computing geopotential height, it says that “geopotential (z) is provided at the surface, but not on individual model levels,” But when I go to the MARS archive, it shows that geopotential is available on all 137 levels. Is there a difference between this data and calculating it using the script? Thank you

please have a look here: ERA5: data documentation - Copernicus Knowledge Base - ECMWF Confluence Wiki