diff --git a/debian/rules b/debian/rules
index 39b41f4..657c782 100755
--- a/debian/rules
+++ b/debian/rules
@@ -7,6 +7,7 @@
 
 # Override setuptools_scm's version detection.
 # setuptools_scm requires git tags to be present in the repository.
+# https://github.com/pypa/setuptools_scm/issues/549
 export SETUPTOOLS_SCM_PRETEND_VERSION=4.1.0
 
 # Disable inclusion of private libraries in non-standard locations.