Civilization – How does population requirement work in Civilization VI

Unfortunately, there doesn't seem to be an easy way to do this in-game. However, much of the code isn't hidden, but is in easily modifiable .lua files, specifically WorldInput.lua.

https://www.reddit.com/r/civ/comments/58q3qj/psa_guide_on_how_to_enable_wasd_andor_other/

This link contains several examples of how to add new hotkeys. For example the code snippet

if (uiKey == Keys.YOUR_KEY_HERE) then
    local unit:table = UI.GetHeadSelectedUnit();
    if unit ~= nil then
        UI.LookAtPlot( unit:GetX(), unit:GetY() );
    end
end  

can be used to make the 'C' key center the view on the current unit, and

if (uiKey == Keys.W) then
    UI.SelectNextReadyUnit();
end  

to cycle units.

In the end, the range of new hotkeys is determined by the functions accessible, and I don't see a list of functions yet. Luckily for you, there's already examples of what you want to add.

The better place to find this information is under the victory screen. There's a tab for the culture victory, where you can hover over the incoming tourism icon from each civ (briefcase in the second column) and see the +/- that is affecting your tourism with them.

EDIT: With Screenshots of the suggestion! Here's what I'm talking about, and this may be a bug. The trade screen doesn't always correctly state when the trade route is providing tourism.

As you can see in the trade route screen, I have a currently active route with Russia, but the trade bonus is not considered active in the trade route screen.

But, on the Culture Victory screen, it clearly shows that the cultural bonus is active.