uefi-test-runner/https/README.md: misc

Author: kraxel

uefi-test-runner/https/README.md

@@ -1,4 +1,7 @@
 https ca cert database in efi signature list format
 
-copied over from centos stream 9 where this is available as
+Copied over from centos stream 9 where this is available as
 /etc/pki/ca-trust/extracted/edk2/cacerts.bin
+
+It's the Mozilla Foundation CA certificate list, shipped in
+ca-certificates.rpm, licensed as "MIT AND GPL-2.0-or-later".