The step size is very close to the 271.509 cents of 7-limit orwell temperament and also close to the 271.426 cents of 11-limit orwell. It is almost identical to 12\53, the 53edo orwell generator which is 271.698 cents.
Scale degrees of 7edt
|5||1358.539||928.571||11/5 (11/10 plus an octave)|
|6||1630.247||1114.286||18/7 (9/7 plus an octave)|
Since one step of 7edt is a sharp subminor (7/6) third, three steps are almost exactly 8/5, four steps are very nearly 15/8 and six steps are a bit flat of 18/7, 7edt is the lowest equal division of the tritave to accurately approximate some 7-limit harmony. Seven steps make up a tritave, meaning that 7edt tempers out 839808/823543, the eric comma.