diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index cdf56e09d..e5f8556b7 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -285,6 +285,7 @@ struct CurlDownloader : public Downloader
             }
 
             if (request.verifyTLS) {
+                debug("verify TLS: Nix CA file = '%s'", settings.caFile);
                 if (settings.caFile != "")
                     curl_easy_setopt(req, CURLOPT_CAINFO, settings.caFile.c_str());
             } else {