During first launch of Xcode, the following window shows up:

It should probably be clarified in the docs whether "iOS" option should be ticked here.
It's partially so huge because it downloads emulators and all sorts of junk. But does it download SDKs too or are they included by default? Are the SDKs even needed for Theos if you use the patched SDKs, or rather, do the default SDKs even still work in Theos in latest Xcode?