There is really too little context to be sure what the author meant but the formula looks superficially like the Noether conservation law for vertical variations in point mechanics (rather than field theory). The $\delta$ usually means functional derivatives, cf. e.g. this Phys.SE post. However functional derivatives wrt. velocity does not make sense without further explanation, cf. e.g. this & this Phys.SE posts.
Let us from now on restrict to the case where the Lagrangian $L(q,\dot{q},t)$ only depends on up to first time derivatives. Then the vertical Noether current is a product of a vertical generator and the momemtum $p = \partial L / \partial \dot{q}$. Note in particular that the momentum is constructed via partial differentiation not functional differentiation.