Sorry, I should've clarified that I was asking about whether you had a source for the claim that this legislation will not allow sideloading. I agree regarding the definition!
It uses the word "sideloading" and doesn't appear to have carveouts allowing Apple to block apps for "security" like the EU legislation does. But at the end of the day it really just depends on what their legislators are going to allow Apple to get away with, and Apple will probably attempt bare-minimum compliance at least initially, like they did in the EU.