It doesn't matter what the information was, Khandro. I had a look at this many years ago when it first hit the news and I've largely forgotten the details. But IIRC, some of the information leaked could have jeopardised the lives of US service personnel. It seems to me that Mr Assange had no real idea what the totality of his leaks involved and didn't particularly care. He certainly could not have been aware of the content of all he published and most reports say that Wikileaks has published in excess of ten million documents.
I don't do petitions generally anyway, but if I did I would certainly not sign this one. I don't quite understand how Mr Assange ended up in the UK. It seems he has led quite a nomadic life and has spent a lot of his time hacking into computer systems of foreign nations, harvesting confidential and classified information and publishing it. This is an issue between the US, Sweden and Mr Assange's home nation of Australia (who, it seems have largely abandoned him to his fate). There may be others as I believe New Zealand was the target of one of his hacking exercises. The sooner he is removed from this country, the better.