There are two formats of polars accepted by vrtool.
1- Simple polars, like vendeeglobevirtuel_pro.csv (*.CSV). Files from vrtoutoulz use this format
2- Multisail polars, like this this (*.XML)
They both work. The XML format has separate curves for each sail.
Multisail polars can be created and edited in vrtool Polar Studio module.