Yes. A reference is like an alias, if you modify the original variable it will also be reflected in it and vice versa since it reads from the same place. In the image of your first post a * was used, this is for a pointer.
const ensures it cannot be modified, only copied from. if you remove it and only use (FSlot& Slot : Content){…} any changed to Slot will also affect the index that was referenced from Content.
For example:
std::vector<int> Content = {0, 1, 2, 3, 4, 5};
for(auto Slot : Content)
{
++Slot;
} // Result: {0,1,2,3,4,5}
for(auto& Slot : Content)
{
++Slot;
} // Result: {1,2,3,4,5,6}
for(const auto& Slot : Content)
{
++Slot; // will not compile.
}
You can experiment with code in websites like https://godbolt.org/. Here you also get to see what the compiler is doing (you can ignore it for now).
If you have access to ChatGPT 4 you can paste code and go line by line asking it to explain. Just remember that it can still make mistakes so always test and check with other sources.
Hope it helps. Feel free to ask anything.