In the second beta for Android Q, when the Pixel 3 or Pixel 3 XL is charging, it only states such. It no longer says whether it is charging "rapidly" or "slowly". For instance, when it is charging wirelessly, it'll say "wirelessly charging", when it is plugged in, it'll say "charging".
This is a very minor change in Android Q, but those that do use fast chargers will notice the difference.
Now this is not to say that the charger is no longer charging the phone quickly, because it is. The only difference here is that the text is missing. Which shouldn't be that big of a deal for most people. When you place it on a wireless charger, it will immediately say "wirelessly charging". But things are a bit different when you actually plug it in. It will say "Charging Slowly" at first, then change to "Charging" and stay there. So it does actually tell you it is charging slowly, but only at first.
It's currently unclear whether this was something that was meant to be taken out for Android Q or not. Of course, we'll have to wait and see when the next beta comes out - likely at Google I/O next month. This is not an issue for a lot of people, as mentioned, as most will just plug in their Pixel 3, or place it on a wireless charger, and that's it. The fact that the phone won't tell you how fast it is charging anymore, isn't going to be an issue for the majority of people. But being able to see that their wireless charger is indeed charging at the full 10W instead of the slower 5W, is something that is very useful. And the same can be said for Quick Charge 3.0 and USB-C PD chargers over the regular, slower USB-C chargers out there.
As always, this is a beta, so this may or may not remain this way in the coming future. As with betas, things change from time to time, and there are of course bugs. This might just be something that Google does take out of Android though. Seeing as it is looking to push Android closer to the mainstream user instead of sticking with the Android geeks and nerds. Something that it has stuck with for many years. That has been pretty clear with the Pixel smartphones in recent years.
If you are looking to install the Android Q Beta 2, you can join the Android Beta Program and install it on your Pixel. Once again, it is available for all three lines of Pixel smartphones. That includes the Pixel, Pixel XL, Pixel 2, Pixel 2 XL, Pixel 3 and Pixel 3 XL. So no matter which phone you have, you can install the beta. It's worth noting that it is not recommended to install it on a daily driver, as betas do have issues and that could hinder your daily productivity. And it's really only recommended for developers, so that they can test their apps with the next version of Android before it launches later this year.