`apt-cache policy libqt6svg6-dev` is "Candidate: (none)" on 26.04; the package that carries the Svg headers and Qt6SvgConfig.cmake is qt6-svg-dev. Since gui/CMakeLists.txt landed on main the root build's find_package(Qt6 ... Svg REQUIRED) is live, so a clean 26.04 box could not configure the project at all. Same name in README.md and AGENT-PKG-QA.md. Reported in gui/docs/pkg-qa-requests-m1.md R1. Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_0143aKiohmDiyefJBwHDJJqw