Man pages matching name mpi_comm_ser_errhandler in section 3:

MPI_Comm_ser_errhandler.3.en	debian 10 / lam4-dev
MPI_Comm_ser_errhandler.3.en	debian 11 / lam4-dev
MPI_Comm_ser_errhandler.3.en	debian 12 / lam4-dev