Qt/KDE seems targeting polyglots onto Quick JSON/QML+ECMAscript/WebAssembly heavily influenced by http://merproject.org/ , whereas CopperSpice seems to be continuing from Qt's past Widgets/native C++. Verdigris is at best an isolated small step for those unwilling to head toward Qt's monotonous direction. IMHO Qt's big enough that competing CopperSpice fork will only be beneficial.