Standards. We need more standards!

https://velo.outsideonline.com/gravel/gravel-gear/750d-wheels-700c/
And the nomenclature is equally entertaining.  "27 and one half" at 584mm is between decimal MTB (559mm) and lightweight 26" (590mm), all well below 27"K2 (630mm).  If that makes sense to you then 700D is just the thing.
Traditionally, tire/rim letter sizes are each smaller, starting from A.  Moreover the last new new new 700D (583mm, GT, Schwinn late 1980s) was smaller than 700C so of course this 700D is significantly larger (660mm).
Make of that what you will. I don't get it.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971