======= Flatpak ======= Flathub's builders don't allow internet access during the build; everything that goes into the build must be specified in the manifest. This means meson submodules won't work. Instead, you need to install blueprint-compiler as a module in your flatpak manifest: .. code-block:: json { "name": "blueprint-compiler", "buildsystem": "meson", "cleanup": ["*"], "sources": [ { "type": "git", "url": "https://gitlab.gnome.org/jwestman/blueprint-compiler", "tag": "v0.14.0" } ] } You can keep the submodule configuration--Meson will ignore it if blueprint-compiler is already installed.