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All sorts of things can be reconstructed from their "linear representations". One example is Tannaka (Deligne, Tannaka-Krein, etc.) reconstruction where a group is recovered from its category of representations. Another example includes various versions of Bondal-Orlov theorem, where an algebraic variety (not every) is recovered from its (derived or even usual) category of (quasi)-coherent sheaves. There are further examples of this phenomena.

Question: How does one reconstruct a homotopy type?

Talking through my hat, if $X$ is a homotopy type, one can reconstruct $X$ by Yoneda Lemma from the functor $hom (X, -)$ from the homotopy types to sets. Now vectors bundles on $X$ "remember" part of this: they are roughly morphisms from $X$ to Grassmannians $Gr_n (R^{\infty})$. Somehow, maybe, if you get "enough" spaces: add some nice spaces (like $BG$ for all compact groups, etc) to Grassmannians, then one can reconstruct $X$ from the category of "nice bundles", which are homotopy classes of maps from $X$ to nice spaces.

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    $\begingroup$ A natural version of this question is to consider the symmetric monoidal $\infty$-category of local systems of R-modules (for suitable ring or ring spectrum R) on X, which is the counterpart to 𝑄𝐶(𝑋) in algebraic geometry (and close to your maps to Grassmannians). Then rational / p-adic homotopy theory a la Quillen-Sullivan/Mandell tells you you can recover X from this when it is simply-connected or more generally nilpotent (since cochains on X arise as the self-ext of the trivial local system - for X nilpotent that generates). See Lurie's DAG XIII or (hopefully) somewhere in SAG. $\endgroup$ Commented Jun 27 at 16:16
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    $\begingroup$ In general for this to work you need some condition on a group (arising as $\pi_1(X)$) that will allow you to detect it from its category of R-linear representations. I'm not sure what's the most natural replacement in general (short of going full Yoneda and just thinking about sheaves of spaces on X, which is too tautological). $\endgroup$ Commented Jun 27 at 16:17

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