Sorry if this is well-known already, but I did not see an official and precise statement from Google before - so for those who always wondered what the official period is until the recalibration is triggered (at least on the stock OS) - I just spotted on support.google.com (translated):
"To ensure accurate battery capacity measurement, your Pixel must be fully charged every 10 cycles. This applies even if you have enabled the “Limit to 80%” option. Once your phone reaches 100%, leave it connected to the charger for at least 30 minutes to complete the process."