https://www.sciencenews.org/article/new-way-genetically-tweak-photosynthesis-boosts-plant-growthThis is a pretty big move. One of the factors that slows the rate of photosynthesis is the processes reliance on the enzyme Rubisco, which is supposed to effectively "start" the light-independent parts of photosynthesis by (in effect) taking carbon dioxide and gluing it to other organic chemicals, a process that ultimately creates glucose.
Unfortunately Rubisco is a very old protein that mainly evolved with "mass production" in mind rather than "efficiency". This means it often screws up, trying to take oxygen from its surroundings, effectively creating extra steps as the toxic by product glycolate is created and has to be dealt with in a very convoluted process that I can't remotely remember the details of (I'm no longer an undergrad so I'm not going to bother looking it up). This (a process called photorespiration) seriously decreases the overall efficiency of the process, and means C3 plants (that aren't adapted to have workarounds) don't flourish very well at all in hotter climates. And as C3 plants include among other things, rice, wheat, oat, barley, legumes, fruit trees, spinach, potato, soy, sugar beet and cotton, this seriously limits agricultural productivity for humanity as a whole especially in the tropics.
This is one of the better uses of GM technology tbh. What they're doing is introducing more efficient tools to deal with the aforementioned glycolate, ultimately simplifying the process, while supressing the inefficient metabolic pathway.