diff --git a/sci-biology/muscle/metadata.xml b/sci-biology/muscle/metadata.xml
index ccdff086e20b0..adacdd12bcf1a 100644
--- a/sci-biology/muscle/metadata.xml
+++ b/sci-biology/muscle/metadata.xml
@@ -1,8 +1,11 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
 <pkgmetadata>
-  <maintainer type="project">
-    <email>sci-biology@gentoo.org</email>
-    <name>Gentoo Biology Project</name>
-  </maintainer>
+	<maintainer type="project">
+		<email>sci-biology@gentoo.org</email>
+		<name>Gentoo Biology Project</name>
+	</maintainer>
+	<upstream>
+		<remote-id type="github">rcedgar/muscle</remote-id>
+	</upstream>
 </pkgmetadata>