Take it with you.

Why a download page works this way

A download link is a safety claim. It says the file is there, that its digest was measured from the bytes being served, and — for anything that runs on your machine — that Apple has signed and scanned it. Each of those is checked separately here, and any one of them failing removes the link rather than dimming it. When something is held back, the page says which check failed and what it found instead.