diff --git a/build/build-jasp.sh b/build/build-jasp.sh
index 8f0e89e..4c88353 100755
--- a/build/build-jasp.sh
+++ b/build/build-jasp.sh
@@ -386,8 +386,13 @@ cp -a "$R_HOME_DIR" "$STAGE_DIR$PREFIX/"
 # checkouts that would bloat the tarball without being usable at runtime.
 install -d "$STAGE_DIR$PREFIX/Modules"
 
-log "staging module bundles from ${MODULE_BUNDLES}"
-cp -a "$MODULE_BUNDLES/." "$STAGE_DIR$PREFIX/Modules/"
+# Deliberately do NOT copy Modules/local/*.JASPModule here. `ninja install`
+# has already placed the same packages in Modules/binary_pkgs as a
+# deduplicated, content-addressed store — 677 package directories, in which
+# Rcpp, ggplot2 and the rest of the shared base appear once rather than once
+# per module. The .JASPModule files are the *distribution* form used for
+# on-demand downloads; shipping them alongside the installed form sends the
+# same content twice and took the tarball from 1.86 GB to 4.3 GB.
 
 
 install -Dm644 /work/packaging/org.jaspstats.JASP.desktop \