The following is likely irrevalent to anything meaningful, however, this name, ETAOIN SHRDLU sure sounds like the 8 highest frequency letters of the English language, plus a few, which as I learned them, are ETAONRIS. Just a curiosity.
Very perceptive: That's exactly what it is, more or less. ETAOIN SHRDLU is what typesetters back in the days of big, clunky Linotype machines would enter as gibberish. Linotype keyboards were six columns wide, laid out in order of frequency; ETAOIN SHRDLU was the first two rows. The modern equivalent would be something like QWERTYUIOP.