This is the newest creation date of all posts included in the data dump. The assumption is that most changes up to then are included in the database.
Q&A about the site for builders and users of networked sensors and control devices in the contexts of smart homes, industry automation, or environmental sensors
-- Data dump creation date -- This is the newest creation date of all posts included in the data dump. Select top 1 CreationDate from Posts order by CreationDate desc