diff --git a/index/li/libgtk3/libgtk3-external.toml b/index/li/libgtk3/libgtk3-external.toml
index 984fe583..4ae527b2 100644
--- a/index/li/libgtk3/libgtk3-external.toml
+++ b/index/li/libgtk3/libgtk3-external.toml
@@ -8,4 +8,5 @@ maintainers-logins = ["Fabien-Chouteau"]
 kind = "system"
 [external.origin."case(distribution)"]
 "debian|ubuntu" = ["libgtk-3-dev"]
+arch = ["gtk3"]
 msys2 = ["mingw-w64-x86_64-gtk3"]