Is there are classification of the equivalent of a developable surface in $\mathbb{R}^4$?
Analogous to: planes, cylinders, cones, and tangent developables in $\mathbb{R}^3$?
Here I am imagining "developing" a 3-dimensional manifold embedded in $\mathbb{R}^4$ into
$\mathbb{R}^3$.

I would appreciate any suggestions for source materials here.  My only source is one page (p.342) in Hilbert and Cohn-Vossen (_Geometry and the Imagination_), in which they say: in $\mathbb{R}^4$

> there are surfaces that are isometric to the Euclidean plane in the small but are not ruled.

But now I see from the comments that this must mean a two-dimensional surface embedded
in $\mathbb{R}^4$, which is not exactly what I seek.

A precise definition of _developable 3-manifold_ in $\mathbb{R}^d$ would also be much appreciated.
Thanks for pointers!