This is one of the potential files. This specifies the parameters relating to pure elements of Aluminum and Magnesium. It is also possible to have parameters of other pure elements. That way you can have one library.meam file for all alloy potentials and have different files for parameters describing pair interactions between different elements.

#meam data Iron, Vanadium
# elt        lat         z       ielement     atwt
# alpha      b0          b1      b2           b3      alat    esub    asub
# t0         t1                  t2           t3              rozero  ibar
'Fe'        'bcc'        8.      26           55.847
5.07292627   2.935       1.00    1.00080073   1.00    2.866   4.29    0.89
1.0          5.13579244          4.12042448   -2.7            1.      0
'V'         'bcc'        8.      23           50.942
4.83265262   4.113       1.00    1.00095022   1.00    3.04    5.3     1
1.0          4.20161301          4.09946561   -1              1.      0