The drop folder
ZIPs left in the incoming folder are imported automatically on the hourly job, or immediately if you ask. Convenient when your build process already writes a file somewhere.
The product is worked out from the folder inside the ZIP, not its filename, and the version is read from the plugin header — so a ZIP named wrongly still publishes correctly, and a ZIP named right but built wrong does not slip through.
A file still being uploaded is left alone and picked up on the next scan, rather than being opened half-written and reported as corrupt.
The exact folder is printed on the Releases screen. If a scan finds nothing, check what you are looking at is the path shown there.