firefox-db2pem: mention what "certutil" the script uses

... and the Debian package that provides it.

Closes #14806

diff --git a/scripts/firefox-db2pem.sh b/scripts/firefox-db2pem.sh
index a45a881db89bbbbafe7754d9a16167a6852bbfa8..57252b40578e9da4de356e9bf42fbb3eaf62babc 100755 (executable)
--- a/scripts/firefox-db2pem.sh
+++ b/scripts/firefox-db2pem.sh
@@ -26,6 +26,9 @@
 # It extracts all ca certs it finds in the local Firefox database and converts
 # them all into PEM format.
 #
+# It uses the "certutil" command line tool from the NSS project to perform the
+# conversion. On Debian it comes in the "libnss3-tools" package.
+#
 
 set -eu