It seems like you're referring to the availability of Windows versions for download from TechNet or MSDN accounts. These platforms are typically used by IT professionals and developers to access Microsoft software and tools for testing and development purposes.
If you have access to a TechNet or MSDN account, you can often download the Release to Manufacturing (RTM) versions of software before they are widely available to the public. RTM versions are essentially the final release candidates that are sent out to manufacturers to be pre-installed on devices.
Downloading the RTM version through these accounts can give you early access to the latest features and updates before they are officially released to the general public. If the links for the RTM versions have just been posted and are set to go live around 8pm PST, it's a good opportunity to get your hands on the newest Windows version for testing or development purposes.
Keep an eye out for any notifications or updates on TechNet or MSDN around that time, so you can download the RTM version and start exploring the new features and improvements it offers.