diff --git a/bin/fdroid-docker-builder.sh b/bin/fdroid-docker-builder.sh
index 82d3c8e..4c1f87d 100755
--- a/bin/fdroid-docker-builder.sh
+++ b/bin/fdroid-docker-builder.sh
@@ -1,55 +1,58 @@
 #!/bin/bash
 
 set -euo pipefail
 
 if [ -z "$1" ]; then
     echo "Uso: $0 <cartella-sorgente>"
     exit 1
 fi
 
 SOURCE_DIR="$(realpath "$1")"
 
 # https://hub.docker.com/r/fabmazza/android-build-fdroid
 # https://gitlab.com/fabmazz/android-fdroid-build-container/-/tree/ubuntu
 IMAGE_NAME="${IMAGE_NAME:-fabmazza/android-build-fdroid:ubuntu}"
 
+# TODO: understand the correct Gradle cache path, so maybe we should drop this line:
+#       https://gitlab.com/fabmazz/android-fdroid-build-container/-/blob/10ed7b902a1420bd6380893ae76999f555bbccff/launch_build_local#L23
+#       https://gitlab.com/fabmazz/android-fdroid-build-container/-/blob/ubuntu/launch_build_local#L23
 DOCKER_GRADLE_CACHE="${DOCKER_GRADLE_CACHE:-$HOME/.cache/fdroid-docker-builder-gradle}"
 
 # Eat the first argument.
 # So we pass all the other shit to gradle.
 shift
 
 if [ ! -d "$SOURCE_DIR" ]; then
     echo "Errore: '$SOURCE_DIR' non è una cartella valida"
     exit 1
 fi
 
 if [[ "$UID" = 0 ]]; then
         echo "Do not run as root."
         exit 2
 fi
 
 mkdir --parents "$DOCKER_GRADLE_CACHE"
 DOCKER_GRADLE_CACHE_REALPATH="$(realpath "$DOCKER_GRADLE_CACHE")"
 
 GID=$(id -g)
 
 echo "[INFO] User info: $(id)"
 echo "[INFO] UID=$UID"
 echo "[INFO] GID=$GID"
 echo "[INFO] IMAGE_NAME=$IMAGE_NAME"
 echo "[INFO] SOURCE_DIR=$SOURCE_DIR"
 echo "[INFO] DOCKER_GRADLE_CACHE=$DOCKER_GRADLE_CACHE"
 echo "[INFO] DOCKER_GRADLE_CACHE_REALPATH=$DOCKER_GRADLE_CACHE_REALPATH"
 
 ## From this point, say what we are doing.
 set -x
 
 docker run \
   -e DESIRED_UID="$UID" \
   -e DESIRED_GID="$GID" \
   --rm \
   -v "$SOURCE_DIR":/home/vagrant/appbuild:Z \
   -v "$DOCKER_GRADLE_CACHE_REALPATH":/home/vagrant/.gradle \
    "$IMAGE_NAME" \
   launch_build_local $@