Hi Clint, The cgit has an atom feed https://git.zx2c4.com/wintun/ and you can of course enumerate tags using the http dumb protocol: https://git.zx2c4.com/wintun/info/refs . The github mirror also has its own notification stuff.
I could start sending [ANNOUNCE] emails for minor wintun updates, if you really think that's necessary, but so far, it seems like it's mostly a smaller group of developers using it. Jason