rsb-spblas.h(3) on Linux
The text 5579c2d50aa9, as Debian 11 (Bullseye) shipped it.
rsb-spblas.h - A Sparse BLAS interface (see http://www.netlib.org/blas/blast-forum/) to librsb. Level 1 (vector-vector operations) is supported in a basic way. Level 2 (sparse matrix-dense vector operations) is supported fully. Level 3 (sparse matrix-dense matrix operations) is supported as a wrapper around Level 2.