Make linkchecker more chatty

conf.py

@@ -2,6 +2,10 @@
 # Here it is useful to allow the configuration to be maintained elsewhere
 # from starterkit_ci.sphinx_config import *  # NOQA
 
+import http.client
+
+http.client.HTTPConnection.debuglevel = 1
+
 project = "Key4hep"
 copyright = "2020, Key4hep"
 author = "Key4hep"
@@ -39,11 +43,15 @@
 #    f'_static',
 # ]
 
+
+# linkcheck_request_headers = {
+#     "https://opensource.org": {"User-Agent": "Python-urllib/3.12"}
+# }
+
 linkcheck_ignore = [
     r"https://twiki.cern.ch/twiki/bin/view",  # TWikis might need login
 ]
 
-# linkcheck_request_headers = {r"https://opensource.org": {"User-Agent": ""}}
 
 myst_heading_anchors = 3