WHT.day reads what each save is about. When you search, it looks for saves whose meaning is close to what you asked for, and separately for saves that contain your words. The two are blended, so a save that matches both ways rises to the top and the closest matches come first.
Short searches get extra help. “Digital ID” on its own says little, so WHT.day first works out the subject you mean — digital identity systems, biometric checks, online age verification, digital currencies — and searches for that. In a real archive, that surfaced an age-verification rollout, a national digital-currency launch and a government data-sharing deal, none of which said “digital ID”. Results found only by meaning carry a small Related label so you can tell them apart.