The SoilGrids FAQ says:
What if I did not find an answer to my question?
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From What is "SoilGrids"? it appears to be an open data product.
Is the community comfortable with all technical SoilGrids questions, other than its 23 Frequently Asked Questions, being diverted to GIS SE?
This answer to Allowing GIS SE to be support for particular software products? may provide guidance for determining the relationship we wish to have with the SoilGrids project.