Twitter converts the string 'hashtag' in its URLs

I follow several 'hashtag related' accounts for the sake of my web app. Came across the user @hashtag https://twitter.com/hashtag

Tried to see their followers: https://twitter.com/hashtag/followers redirects to https://twitter.com/i/#!/search/?q=%23followers

Clicked: https://twitter.com/hashtag/following and got https://twitter.com/i/#!/search/?q=%23following

https://twitter.com/hashtag/lists worked as expected (huh?)

mobile.twitter.com URLs do not follow this behavior though

Is this a Twitter account?

(edited for grammar)