diff --git a/.gitignore b/.gitignore
index c22f3c4..9ac56d9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -189,3 +189,10 @@ android/build/
 android/app/build/
 android/local.properties
 .kotlin/
+
+# Locally-downloaded APKs for emulator/device testing.
+#
+# CI builds these and attaches them to the run as artifacts; a copy sitting in
+# the working tree is a convenience, never a source. Ignored because they are
+# ~57 MB and `git add -A` would otherwise put one in history forever.
+*.apk