When Apple announces a new iPhone, we typically get a full rundown on its specs like cameras and display size and resolution. However, Apple typically leaves out the battery size and RAM of its new phones, and that was the case with the iPhone SE yesterday. That's where carriers and retailers come in.
We also learned at that time that the iPhone 8 had 2GB of RAM but the iPhone 8 Plus had 3GB. So it appears that Apple opted to give the iPhone SE a little extra RAM like it did with the 8 Plus rather than sticking with the 2GB found in the regular iPhone 8.
To compare, the iPhone 11 and 11 Pro both have 4GB of RAM. The iPhone 11 starts at $699, though, and the iPhone SE at $399. And the iPhone SE does have the same A13 Bionic processor as the iPhone 11 and 11 Pro, so the SE isn't losing much in the way of performance compared to its flagship siblings.