Why the Equality Axioms are considered as logical axioms? This question is from Introduction to Mathematical Logic by Elliot Mendelson , page 94-95 , First order theories with equality.There is a line which is kind of confusing for me.

The numbering (A6) and (A7) is a continuation of the numbering of the logical axioms.

Here , (A6) and (A7) are the following axioms:
$(A6)$ $(\forall x_1)x_1=x_1$ 
$(A7)$ $x=y \to (\mathscr B(x,x) \to \mathscr B(x,y))$
My question is , why they are considered logical axioms ? Shouldn't they be in the category of proper (or non-logical) axioms?
What is your criterion of what counts as a &quot;logical constant&quot;? The connectives and first-order quantifiers count as logical notions -- but why?
There are various stories on the market for demarcating the logical constants.  Depending on the details, some count the identity predicate as a logical constant, some don't. For an accessible discussion of some of the options here, see e.g. https://plato.stanford.edu/entries/logical-constants/
But certainly, some standard accounts do treat the notion of identity as logical: it is topic neutral and general enough; it is governed by introduction and elimination rules in the right sort of way, and so on. Mendelson is not at all going out on a limb in treating the identity laws as logical.
I think Mendelson did not even say that $(A6)$ and $(A7)$ are logical axioms.I completely misinterpreted the above line.
@James Hanson Already answered my question.They are indid non-logical because they are not logically valid.An axiom (generated from a schema) is a logical axiom iff it is logically valid.
Second , The author meant to say that he would number the non logical equality axioms according to the continuation of the numbering of the logical axioms (There are 5 logical axioms in this case).Not that the equality axioms themselves are logical axioms.