diff --git a/build-aux/flatpak/org.gtk.Demo4.json b/build-aux/flatpak/org.gtk.Demo4.json
index 1b7a542d80..7c6ce1a7de 100644
--- a/build-aux/flatpak/org.gtk.Demo4.json
+++ b/build-aux/flatpak/org.gtk.Demo4.json
@@ -63,6 +63,36 @@
                 }
             ]
         },
+        {
+            "name" : "libsass",
+            "buildsystem" : "meson",
+            "builddir" : true,
+            "config-opts" : [
+                "--libdir=/app/lib"
+            ],
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://github.com/lazka/libsass.git",
+                    "branch" : "meson"
+                }
+            ]
+        },
+        {
+            "name" : "sassc",
+            "buildsystem" : "meson",
+            "builddir" : true,
+            "config-opts" : [
+                "--libdir=/app/lib"
+            ],
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://github.com/lazka/sassc.git",
+                    "branch" : "meson"
+                }
+            ]
+        },
         {
             "name" : "gtk",
             "buildsystem" : "meson",
diff --git a/build-aux/flatpak/org.gtk.IconBrowser4.json b/build-aux/flatpak/org.gtk.IconBrowser4.json
index 1c14244999..49a0c2a308 100644
--- a/build-aux/flatpak/org.gtk.IconBrowser4.json
+++ b/build-aux/flatpak/org.gtk.IconBrowser4.json
@@ -63,6 +63,36 @@
                 }
             ]
         },
+        {
+            "name" : "libsass",
+            "buildsystem" : "meson",
+            "builddir" : true,
+            "config-opts" : [
+                "--libdir=/app/lib"
+            ],
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://github.com/lazka/libsass.git",
+                    "branch" : "meson"
+                }
+            ]
+        },
+        {
+            "name" : "sassc",
+            "buildsystem" : "meson",
+            "builddir" : true,
+            "config-opts" : [
+                "--libdir=/app/lib"
+            ],
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://github.com/lazka/sassc.git",
+                    "branch" : "meson"
+                }
+            ]
+        },
         {
             "name" : "gtk",
             "buildsystem" : "meson",
diff --git a/build-aux/flatpak/org.gtk.WidgetFactory4.json b/build-aux/flatpak/org.gtk.WidgetFactory4.json
index bcbee387e7..e9893bb0d5 100644
--- a/build-aux/flatpak/org.gtk.WidgetFactory4.json
+++ b/build-aux/flatpak/org.gtk.WidgetFactory4.json
@@ -63,6 +63,36 @@
                 }
             ]
         },
+        {
+            "name" : "libsass",
+            "buildsystem" : "meson",
+            "builddir" : true,
+            "config-opts" : [
+                "--libdir=/app/lib"
+            ],
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://github.com/lazka/libsass.git",
+                    "branch" : "meson"
+                }
+            ]
+        },
+        {
+            "name" : "sassc",
+            "buildsystem" : "meson",
+            "builddir" : true,
+            "config-opts" : [
+                "--libdir=/app/lib"
+            ],
+            "sources" : [
+                {
+                    "type" : "git",
+                    "url" : "https://github.com/lazka/sassc.git",
+                    "branch" : "meson"
+                }
+            ]
+        },
         {
             "name" : "gtk",
             "buildsystem" : "meson",