Lua:findWindow
findWindow(classname OPTIONAL, caption OPTIONAL): windowhandle - Finds a window with the given classname and/or windowname
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-findwindowa
print( findWindow("WTWindow", "Game") )
Because classname is optional, this will also work:
print(findWindow(null, "Cheat Engine 7.4"))