This seems to be much nicer than ncurses, since it's a declarative interface rather than an imperative one. Outside of Flexbox, there's nothing HMTL-specific in the API. An XML-like syntax is used because UI on most platforms is conceived as an ordered tree structure, such as Windows (XAML), Apple (XIB), Android, and Web (HTML).

The built-in components are all conceived as TTY-native ideas, not as HTML concepts:

    <Text>
    <Box>
    <Newline>
    <Spacer>
    <Static>
    <Transform>