I doubt very much that it is legit.
Different websites:
http://en.pangu.io (official pangu)
http://pangu8.com/83.html (alleged semi-JB)
Also no mention on the official site, nor on the official twitter of Pangu:
https://twitter.com/PanguTeam
Nothing on reddit accept a warning that it is fake:
http://www.reddit.com/r/jailbreak/comments/33yvjh/about_the_83_semi_jailbreak/
Nothing from the leading Dev's, not even from i0n1c, which would probably be the first to comment (or condemn) especially if it concerns Pangu.
Also it involves installing a profile, which is a security risk if unsure from whom it is or what is does.
All-in-all: Stay Away!