My brother did Florida Virtual School and graduated in 2011 or so. It was actually pretty great, and what they should have switched all the students to during COVID. It's exactly what it sounds like, online coursework, just like if you've ever taken a college class online, but its a public high school option meaning its free. Some stuff doesn't work quite as well, the lab kit they sent my brother to use wasn't quite as good as my in person lab classes. Florida actually invested the time and money to make it good because a lot of child actors and some of the kids training at sports schools use it.
Edit: to clarify, "public" in the US means state government funded, I'm aware that some places mean the opposite when they talk about public/private schools.
It's a public school that's attended primarily online.
When I was enrolled in one, they had us do 99% of our work at home, and we could do the work at our own pace, but we had to come in to the building to take the more important tests to move to the next semester-equivalent. That was to make sure that we weren't cheating like we were fully able to do for the regular tests, because this was before spyware was the norm.
It was great for anyone who could stay motivated to do school work and would go out of their way to interact with other students, and it was the worst possible method of schooling for my lazy, unsociable ass. I'd likely not have graduated if my high school hadn't started giving what basically amounted to a GED test for seniors who couldn't pass their classes in time. I knew the stuff, I just refused to actually do the stuff. Highly recommend for extraverts. Cannot recommend for introverts.