/usr/share/nsis/Contrib/Modern UI 2/ is in nsis-common 2.50-1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/nsis/Contrib/Modern UI 2/Deprecated.nsh
/usr/share/nsis/Contrib/Modern UI 2/Interface.nsh
/usr/share/nsis/Contrib/Modern UI 2/Localization.nsh
/usr/share/nsis/Contrib/Modern UI 2/MUI2.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/
/usr/share/nsis/Contrib/Modern UI 2/Pages.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/Components.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/Directory.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/Finish.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/InstallFiles.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/License.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/StartMenu.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/UninstallConfirm.nsh
/usr/share/nsis/Contrib/Modern UI 2/Pages/Welcome.nsh