diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index a5ef93d6..d60c6908 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -101,6 +101,9 @@
     - 'name': 'Set up Docker Buildx'
       'uses': 'docker/setup-buildx-action@v1'
     - 'name': 'Run snapshot build'
+      # Set a custom version string, since the checkout@v2 action does not seem
+      # to know about the master branch, while the version script uses it to
+      # count the number of commits within the branch.
       'run': 'make SIGN=0 VERBOSE=1 VERSION="v0.0.0-github" build-release build-docker'
 
   'notify':