diff --git a/.travis.yml b/.travis.yml
index 415b238..1864bc5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,7 @@ go:
   - 1.12
 
 before_install:
+  # We need Python to run pygmentize for generating HTML.
   - sudo apt-get update
   - sudo apt-get install python