Ha, a proof that by watching YouTube videos you learn something.
This was covered by one of my favorite series on YouTube. Here is the particular video: https://www.youtube.com/watch?v=fD-R35DSSZY
I can confirm all of it for Germany as well (except the Italian serpentine road synchronization hack).
I flash lights for oncoming traffics because of danger or police checks.
I flash warning lights (or raise right hand) for thank you. Others do as well (especially buses, when you let them out of the bus stop, since in Germany they don't have the right of passage leaving a bus stop)
I learned that truck drivers (and buses) flash left, when it's not safe to overtake.
There are also some official rules regarding bus flashing at a bus stop (right, warning). But most of drivers ignore that.
We use Intel Compiler mainly on supercomputers with Intel CPUs. IT can produce faster code. However it is not great to work with it. It lacks features of the newer standard and it is really slow. Usually we develop with clang or GCC and then we go on the cluster.
I wonder what the author would do, when performance is critical. Today too many people rely on fast cpu and large memory. There are lots of applicants, where you need to optimize.
I use VS Codium. That is the opensource packaging without Microsofts calling home functionality: https://vscodium.com,
with the Vim and code-d extension.
You also will want to change some shortcuts, so for example you can switch to terminal and back with CTRL+~, in order to run/test your app quickly.
I would also like to have a full fledged IDE like i have for Python with pycharm, but currently nothing is available.