As far as I know, we currently export access to nonzero values to sparse vectors and sparse column views, via SparseArrays.nonzeros. However, the corresponding SparseArrays.nonzeroinds is not exported, which makes these two methods of SparseArrays.nonzeros quite useless.

I think we should just write docs and export it: Users of sparse vectors / sparse column views are likely to rely on SparseArrays.nonzeroinds already, and would already be affected by any reorganization.