These L-functions satisfy a functional equation with $$\Gamma$$-factors \begin{aligned}\Gamma_\R(s + i \mu_1)\Gamma_\R(s + i \mu_2)\Gamma_\R(s + i \mu_3)\end{aligned} with $$\mu_j\in \R$$ and $$\mu_1 + \mu_2 + \mu_3 = 0$$. By permuting and possibly taking the complex conjugate, we may assume $$\mu_1 \ge \mu_2 \ge 0$$, so the functional equation can be represented by a point $$(\mu_1, \mu_2)$$ below the diagonal in the first quadrant of the Cartesian plane.
The dots in the plot correspond to L-functions with $$(\mu_1,\mu_2)$$ in the $$\Gamma$$-factors, colored according to the sign of the functional equation (blue indicates $$\epsilon=1$$). Click on any of the dots for detailed information about the L-function.