How to calculate Cochran Q value in sample size model?

[Y-Isaac]

Hi, thanks for this useful tool.

I want to consult you that the process of calculation of Cochran Q value (also named HetChiSq in software). I have understood the heterogeneity calculation process in inverse variance weighting, but I am not quite sure how this process is implemented in sample size weighting. Is there a specific calculation formula for me to learn? I don't seem to be able to find the answer in the manuscript related to metal.

Best regard