GATK FilterMutectCalls parameter max germline posterior ?

Question

[jackyen]

Hello,

I'm working on a pipeline and running mutect2. I came across the FilterMutectCalls which can add some annotation on the variants. I'm particularly interested in filtering out the germline variants. There's a "--max-germline-posterior" parameter which default is set at 10% of "posterior probability" Could someone explain what does this algorithm work? Is it based on frequency? definition "Maximum posterior probability that an allele is a germline variant" Thank you