st: Why does nl call all parameters as "_cons"?

[Richard Sweeney <sweeney.richard@gmail.com>]

I'm using nl to estimate a CES production function. Here is a simple example:

eststo: nl (logy = {bA: const log_tot_cap} + log( (exp({b: const
xb})*x1^({rho}) + x2^({rho})) / {rho} ) ), ///
init(rho 2) eps(1e-5) hasconstant(bA_const)

Stata's default output looks as expected. However, when I use esttab
(or matrix list), the coefficients all have "_cons" added on at the
end. For example:

----------------------------
                      (1)
                     logy
----------------------------
bA_const
_cons              -3.354***
                (-129.98)
----------------------------
bA_log_tot~p
_cons               0.589***
                 (204.35)
----------------------------
b_const
_cons               0.102***
                   (5.14)
----------------------------
b_xb
_cons              -0.114***
                 (-11.49)
----------------------------
rho
_cons               0.438***
                 (162.21)
----------------------------
N                   32704
----------------------------

Can someone please tell me what this means? In what sense are these
parameters constant?

Finally, does anyone know how to suppress this suffix? It makes it
difficult to refer to specific variables later on when using esttab,
since they're all called "_cons".

Thank you

Rich
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