I recently used webench to create an "mains" ac to 5v dc isolated converter (see https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=829567FEA10E90C3)
i noticed that the output has a resister Rpl between 5v+ and GND
while on the UCC24636 datasheet (pg 23) i can see Rpl but no mention of calculating its value or its reason for being there