[Koha] Adding an encryption_key to koha-conf.xml

Hi All Just upgraded tonight from Koha 21.11.05.000 to 22.05.00-1 That all went fine. The About Koha page now says: "Warning: You are missing the <encryption_key> entry in your koha-conf.xml file. Please generate a key." I can see a place for this is the koha-conf-site.xml.in file (and a suggestion to use pwgen 32) but how do you process this to the koha-conf.xml files for each site? The "pwgen 32" suggests this should be 32 characters and is itself just something that no one should be able to guess. So I can can just put anything in there that is long and complex? I could not find anything about this is the docs or wiki or recent emails, just the patch for it in the github repo via Google. Thanks Mike