Leaves used for black tea ferment for days before they're heated, causing the leaves to blacken and many chemical changes to happen within them.

而制作红茶的叶子会在被加热之前先进城数日的发酵，导致这些叶子变成黑色，并且在其中发成多种化学反应。

youdao

Dinaburg said he became interested in this topic last year at Black Hat when a friend, Robert Edmonds, and Paul Vixie presented on a study of changes observed within the domain name system (DNS).

FORBES: Bitsquatting: Machine-Garbled Internet Connections