Speeding up the Unreal Editor launch (again) by not loading 1585 files

After writing one article on how to speed up Unreal’s editor launch by not spawning 38000 tooltips and one on how to speed it up further by not opening 5500 files and getting the described fixes merged in for 5.8, I sort of stopped looking into the topic for a while. Surely, the low-hanging fruits were all found by now, right? Finding another substantial optimization wouldn’t be easy. Well, time passed, and my curiosity took the better of me. “Just one short profiling session.” I told myself, while starting up the profiler once again. And after only a minute of looking through the Superluminal trace, I found something that looked like I found gold: Spending up to 8 seconds in one function call? This seems worth investigating, especially since it already sounds like it’s doing a lot of unneeded work. Loading “all culture data”? I’d prefer “loading the minimum amount of culture data needed to get to the editor”, thank you very much. To be fair, after multiple rounds of profiling, it was…