Allowing me to bikeshed for a second, was the progress bar a stylistic choice on this blog or part of some default styling? I keep seeing it pop up on random si

Allowing me to bikeshed for a second, was the progress bar a stylistic choice on this blog or part of some default styling? I keep seeing it pop up on random sites and I can't help but think people are developing on browsers that elide the scrollbar. Adding it back in seems like a signal that it was actually useful information for the user. I know safari removes it, not sure about chrome. Firefox does not remove it on desktop but does on mobile.