The Kubu vscode theme is part of a larger set of themes for the KDE display manager.
Extended language support
Apart from syntax highlighting for all the languages supported in vscode by default (like Python, Javascript, etc.), Kubu also implements special coloring rules for tokens generated by some other third-party syntax highlighting extensions:
Haskell: coloring for the tokens defined by the justusadam.language-haskell extension.
SWI-Prolog: coloring for the tokens defined by the arthurwang.vsc-prolog extension.
Rust: coloring for the tokens defined by the dustypomerleau.rust-syntax extension.
C#: coloring for the tokens defined by the ms-dotnettools.csharp extension.
Coq: color for the Coq proving language based on the ruoz.coq extension.