libmumps-seq-5.2.1 5.2.1-2 (arm64 binary) in ubuntu focal

 MUMPS implements a direct solver for large sparse linear systems, with a
 particular focus on symmetric positive definite matrices. It can
 operate on distributed matrices e.g. over a cluster. It has Fortran and
 C interfaces, and can interface with ordering tools such as Scotch.
 .
 This package is built the MUMPS libseq dummy sequential MPI library.
 Unless you know that you specifically need this, then you almost
 certainly want the libmumps-5.2.1 package.