Kirby and Siebenmann obstruction for $D neq 5$?

In 1984 old Book "Instantons_And_Four-Manifolds_Instantons and 4-Manifolds" in p.1 by Dan Freed and Karen Uhlenbeck: it says

"In 1968 Kirby and Siebenmann determined that for a topological manifold M of dimension at least five ($D=5$). there is a single obstruction $$a(M) in H^4(M;Z_2)$$ to the existence of a PL structure."

My question is that are there examples outside dimension D=5 have this obstruction $ a(M) in H^4(M;Z_2)$? For example

• at $D=4$, say $E_8$ manifolds?

• at any $Dgeq 4$, say $E_8 times T^{D-4}$ manifolds?

If yes, of if there are known examples, why Dan Freed and Karen Uhlenbeck only stated $D=5?$