At GitHub they limit you to 29 consecutive (calendar) days of leave. However anything over 14 days needs to be approved by your manager. And then there is a lower limit to the days you must be in the office to collect a full bonus. Finally there is a maximum time you can take off in a half year which directly relates to a negative employee review.
So it’s not unlimited, but recruiters won’t tell you the nuance.. you find out when you read the handbook and talk to your manager on day 1. But why take leave anyway, I watched someone get hired, literally do nothing, and it took 7 months for the company to let them go