to build/install/test:
- flatpak-builder --install-deps-from=flathub --repo=repo --ccache --force-clean --user build org.netsurf_browser.NetSurf.yaml
- flatpak build-update-repo repo
- flatpak remote-add --no-gpg-verify --user netsurf-test repo
- flatpak install --user netsurf-test org.netsurf_browser.NetSurf
- flatpak run org.netsurf_browser.NetSurf