In most metrics weekends are included as is. For example when we're talking about a cycle time of a pull request, 14 days means two full calendar weeks.
This is a trade-off with the numbers being understandable and reflective of calendar time, while helping you drive improvement when the team is already doing great. There are other holidays and out-of-office days anyways included in these numbers, so we felt that just excluding weekends now would give you a false sense of accuracy.
Over time the numbers will even out.
We have an exception with the review times, since it's one of the more action-oriented metrics and there's a related Working Agreement. The review time excludes weekends so that the team can focus on getting a quick turnaround time.