You can use: <link rel="alternate" type="application/rss+xml" title="Title Of your Website RSS Feed" href="Url of feed" /> Which is not technically a meta tag but it goes in the head section and it seems to work quite well. Thank You
No one can know that tag. It's a secret. Of course, if you meant something else, you should learn to write.
People can know what Meta tags you are using if they look at the source code of your page or of the xml file IT