This is one of the potential files. This specifies the parameters relating to pure element of Tungsten. 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 Tungsten in LAMMPS format
# elt        lat     z       ielement     atwt
# alpha      b0      b1      b2           b3    alat    esub    asub
# t0         t1              t2           t3            rozero  ibar
W            bcc     8       74           183.85
5.62777409   3.978   1.00    1.00065894   1.00  3.165   8.66    0.98
1.0          3.16353338      8.24586928  -2.7           1.0     0