Leslie Robertson, who lead the WTC structural engineering team along with John Skilling, is on tape making the 707 claim, but no surviving documentation has been uncovered to reveal the specific scenario that was modeled or the calculations used.
An important reason why the towers survived the impacts at all was the presence of the two hat trusses, which allowed the increasingly unsupported loads to be redistributed to the surviving exterior columns. Najib N. Abboud of Thornton-Thomasetti has given a detailed account of the findings of the forensic investigation that's available on Youtube[1].
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As someone that has used module systems from dojo to CommonsJS to AMD to ESM with webpack and esbuild and rollup and a few others thrown in ... this statement hits hard.
https://www.imdb.com/title/tt1460448/