It has two frequency lists, for dictionary words and for words in text. The idea is to hit the most frequent letters first.
For my strategy of using ADIEU and SNORT, according to dictionary frequencies, it hits the 1, 2, 3, 4, 5, 6, 7, 8, 11 and 12 most commonly occurring letters. It also does very well for the text frequencies.
WikipediaLetter frequency is the number of times letters of the alphabet appear on average in written language. Letter frequency analysis dates back to the Arab mathematician Al-Kindi (c. 801–873 AD), who formally developed the method to break ciphers. Letter frequency analysis gained importance in...
https://en.wikipedia.org/wiki/Letter_frequency