All just roughly guesstimating. Fermi Estimation. Well it's blocking 25% of the disc, and that's about 25% of the full sphere, and I'll guess the star is 10% as luminous as the Sun (EDIT: That luminosity is incorrect). All told, about 0.001 solar luminosities. Considering the efficiencies in any conversion process, probably 0.0001 solar luminosities goes to antimatter, a leading fuel for an interplanetary spaceship. So about 3 x 10^24 Watts. In a year, about 10^32 Joules of energy. How much is that? Well here we go https://en.wikipedia.org/wiki/Orders_of_magnitude_%28power%29 https://en.wikipedia.org/wiki/Orders_of_magnitude_%28energy%29 We're looking at a civilization that could feasibly push planets around in its star system, or blow them to smithereens like the Death Star, though both would be major undertakings. Of course we kind of know that already because to build such a megastructure in the first place demands you take planets to pieces. That said, that the energy a Dyson Sphere can produce is comparable to the energy it takes to build tells us something - it tells us that a small Dyson structure can support its own expansion over sensible timescales. But what about spaceships? Well to get something up to most of the speed of light takes energy equal to its own mass energy. So this civilization could each year be sending off an interstellar ship of about 10^15 kg. That assumes a beamed power system to circumvent the rocket equation, it would be less if all the fuel had to be carried. https://en.wikipedia.org/wiki/Orders_of_magnitude_%28mass%29 We're definitely talking building masses, shading into small asteroid masses here. They could probably send a Rama to another star if they wanted.