Your post made me curious so I found this and was able to reverse-engineer my old stats. I knew the streak I had, plus that I had gotten 5 stars on everything since around the 20th game I did, at which point I was -25 from the highest possible star count.
So here I figure p=played, s=stars, sk=streak, b=???, l=last played, dst= distribution of stars.
(Edit: I originally misunderstood the dst as moves left, so the numbers I put in the picture above were wrong. I changed it to “dst”:[0,1,0,3,2,7,100] which is correct. The array matches the distribution shown on the “Statistics” popup you posted a picture of)
(Edit 2: Now looking at the statistics popup again, I guess “b” matches the “best streak” stat.)