--- a/mercurial/patch.py	Sun Oct 06 06:55:49 2019 -0700
+++ b/mercurial/patch.py	Sun Oct 06 12:59:47 2019 +0200
@@ -289,6 +289,7 @@
                             prefix = '# %s ' % header
                             if line.startswith(prefix):
                                 data[key] = line[len(prefix):]
+                                ui.debug('%s: %s\n' % (header, data[key]))
                     else:
                         hgpatchheader = False
                 elif line == '---':