6
Looks like there were no any Kashubs among reference samples for "Polish", because he plots in empty space:
https://vahaduo.github.io/g25views/#NorthEurope
Out of reference samples, "Polish18" is the closest to where this Kashubian guy plots, but still quite far away.
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In Northwest Europe PCA, Kashub plots next to VK157 from Bodzia:
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