The "Pretty Themes" Update
With this update brings a new "Theme" tab that allows you to view your current wallpaper and primary accent, as well as change the normally-hidden secondary accent colour (the one that affects text highlighting and selection).
For now, changing the secondary accent colour requires you to sign out and in for it to take effect, but this might be fixed in the future. Resetting it to defaults can be achieved by shift+clicking the "Update" button. When changing the colour, Windows may hang or become laggy for a few seconds. I have absolutely no idea why this happens but it's non-destructive so just give it a second to catch up.
If you discover any horrendous bugs, feel free to create an issue for them. Also, some AVs still detect MWV as "anomalous" or otherwise potentially malicious. I can guarantee you it isn't the case and you're welcome to check the source, it's just related to how I acquire the values (which is done via the registry and the Windows Management Interface).