You need to be a more specific, I'm afraid.
The fact you wrote "slack" in lower-case indicates you are looking for a slack-desc file for Namecoin. If you have "Slack" in mind instead of "slack", however, then I could guess you're asking for a namecoin Slack channel, just like our Matrix/IRC channels #namecoin and #namecoin-dev. Or is it some Slack identity information you want to publish on the Namecoin blockchain in order to include a decentralization feature in Slack (similar to the Bitmessage client that is able to retrieve Bitmessage identity information from a Namecoin client)?