Some of these have gone stale. Many of them use ambiguous terms like "X lock" which seems to predate WiredTiger or the introduction of intent locks. Some staleness I've found:

• DatabaseHolder::openDb() reads "must be called with the database locked in X-mode", however it actually requires a MODE_IX lock.
• Database::dropCollection() reads "the caller should hold a DB X lock" and that contradicts the documentation stating that dropCollection hasn't taken a strong db lock since 4.2.