It’s not so much debunking as providing an alternative that actually has some rationale behind it. Dark energy is basically a kludge people came up with because the observed data didn’t fit with the predictions of the standard model. However, now we have mounting evidence against the notion of dark energy, and MOND is starting to look like a better overall model. The timescape model proposed in this study seems to complement MOND nicely. MOND modifies gravity to account for observed galactic behavior, so it doesn’t rely on dark energy to explain cosmic expansion, but doesn’t provide a rationale. This study argues that time moves slower in matter-dense areas (like galaxies) and faster in voids, creating the illusion of accelerated expansion.