diff --git a/conf/app.src b/conf/app.src
index 7182f14..a02e340 100644
--- a/conf/app.src
+++ b/conf/app.src
@@ -1,7 +1,7 @@
 SOURCE_URL=https://github.com/glitch-soc/mastodon/archive/07cb948f39464b11959fc506b673a90d9524e519.tar.gz
 SOURCE_SUM=5808362e249689029726b79b799aab7382fc6626a142e54638633b08dee13c76
 SOURCE_SUM_PRG=sha256sum
-SOURCE_FORMAT=.tar.gz
+SOURCE_FORMAT=tar.gz
 SOURCE_IN_SUBDIR=true
 SOURCE_FILENAME=07cb948f39464b11959fc506b673a90d9524e519.tar.gz
 SOURCE_EXTRACT=true