How is the "top 10%" calculated? what metric is this? the playlist in question ("25% Default") has zero visible likes

There was a post about this not too long ago but it was deleted. I had never heard of the playlist they wanted me to share and there were only 2 songs I recognized. Same thing, no likes on the playlist, either. I think the top percentage isn't calculated but someone decided to use "Top 10%" for this popups wording.