Which settings were used to generate contour data?

[blacklion]

I wonder, which setting were used to generate $DATA_DIR/dem/contours/contours-$continent.pbf? Is it SRTM1 or SRTM3 or VIEW data? Which step and simplifying options were used?

I cannot find options which was used in scripts, only options for hill shading data.

Thank you.

[Artoria2e5]

The mapnik folder specifies http://viewfinderpanoramas.org/dem3.html. I think there might be some attribution that can be added about it, given the lots of curating that went into this model.