#3591 quietly introduced the test/staging/ directory without explaining its purpose. Since then more tests have been added there, but I'm failing to find any documentation about it.

• Are test262 runners expected to include or exclude tests in this directory by default?
• Are tests in this directory expected to pass in an engine with a correct implementation of the latest (draft) spec these tests are targeting?
• What are the requirements for someone writing tests to add them to staging, and when can they be moved out of staging?

We're seeing an unusal high failure rate (75% not passing overall) for that directory, so some clarification would be greatly appreciated!