when you said "manifestoes had no meaning whatsoever".
It's a common belief or should I say misbelief? I see so many people that say they will vote for party X and then admit they haven't read a word of their manifesto or election literature. As I said, we increasingly get the politicians our increasingly shallow voters deserve. I believe the two behaviours are linked.
I really do recommend people to scan read manifestoes, it's so easy with pdf downloads and Cntrl F to look for key points of interest but even if not, the major media do dissect them very well as per the Beeb link I gave.
So to the point at hand, Corbyn hasn't put out a manifesto per se but his campaign web site is

imho
http://www.jeremyforlabour.com/ (you need to drill down through it)
Votes at 16, massive giveaways, cripple industry, an invite to bring back Rackmanism, more and more windymills, people to give up cars for nationalised public transport, huge extra expenses for employers and yet we're supposed to believe unemployment won't soar etc etc.
The man trades on a dishonest projection of supposed honesty.