libportal-gtk4-dev 0.6-4 (amd64 binary) in ubuntu mantic

 libportal provides GIO-style C APIs for most Flatpak portals' D-Bus
 interfaces. It is primarily intended for installation in Flatpak runtimes,
 where applications can use it to interact with portals; it can also be
 used to test the portal services.
 .
 See the xdg-desktop-portal package's description for more information
 about portals.
 .
 This package contains development headers and the pkg-config file for
 integration with GTK 4.