Merch is an abbreviation for merchandise. In this case, it means shirts or hats with the Damus logo on them which are sold to support development.
Discussion
It's nostr:npub1h50pnxqw9jg7dhr906fvy4mze2yzawf895jhnc3p7qmljdugm6gsrurqev's gig, right?
Does damus have webmarket now? Or is it a link to external website?
Yes. And it is an external link to https://store.damus.io/?ref=damus_ios_app. I don’t think there are any plans in the near future for Damus to integrate webmarket features.