diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index d0fce1b2ea0ac0189be6142a99d9c1679a7cd897..2a98a64aa1214ae783bd6b7da0f9843f6f96e97e 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -3,6 +3,7 @@ image: "coqorg/coq:latest"
 build:
   stage: build
   script:
+    - opam config list
     - .ci/apt-get.sh ghc cabal-install libghc-language-c-dev libghc-wl-pprint-text-dev libghc-optparse-applicative-dev libghc-data-default-dev libghc-aeson-dev
     - cabal build
     - cp dist/build/digger/digger digger