Cannot open S6 eumetcast files in snap 8

cannot open S6 eumetcast files in snap 8.
I uncompressed the raw .tar eumetcast file into the folder
but snap does not open the xfdumanifest.xml

SNAP is not supporting Sentinel-6.
For altimetry there is a separate toolbox available.
Radar Altimetry Tutorial and Toolbox
But I think it is also not yet supporting S6 data.

Maybe you can work with the netcdf files contained in the SEN6 folder?