There is a pretty decent overview of Sugar buried in this video about One Laptop per Child. We've continued to maintain the platform since 2006. It runs really well on on hardware. Many of the activities are available stand-alone in FlatPak. There is a browser version called Sugarizer. And there are some Sugar Labs activities for the web, such as Music Blocks.
Regarding the comment that kids like computers (and will learn to use them without needing any special enticement), I couldn't agree more. Alan Kaye has been saying as much since the 1970s. But that said, while kids can learn to use computers, are they learning to use computers to learn? The latter is the goal of Sugar: to make the path of least resistance be one where kids engage with powerful ideas while constructing (not being instructed -- they already have plenty of that in their lives). So most of the activities are about building things. And the Sugar Journal is a vehicle for reflection on what they have built.
Rather than condescending to kids, we empower them: Sugar is not just "open source". The kids are only one mouse-click away from seeing the source code of whatever activity they are engaged in. And Sugar provides affordances for the kids to then modify the code -- taking full ownership of their tools. Not every kid goes this deep into Sugar, but many do.