I had hard to find them, but the emojis are actually located in another git repo: discourse-emojis/dist/emoji at main · discourse/discourse-emojis · GitHub
I have checkout the discourse git source to the state where the directory public/images/emoji were existing, in the git commit 6b6cffdf85444204c171d7fb372b916938b17e54, and I have copied this directory to an own https indexed website.
Following the instructions of @Falco I went to the discourse configuration and set DISCOURSE_EXTERNAL_EMOJI_URL to that https url, in my first attempt the configurator was “thinking” (scanning?) for around 10 seconds, it didn’t had the directory on that moment, so when I finished to copy it I inserted it again but this time was not like scanning anything, same if i insert any url… in the end, im adding a correct url, but the “emoji set” doesn’t update with new / different names, what im doing wrong? 