[superkuh]

There was a source leak a while back talked about here on HN: https://news.ycombinator.com/item?id=13417307. I'm still seeding this torrent and you may find it elsewhere. http://superkuh.com/opera12v15presto-source.torrent

[sovok_x]

Opensource is not about having a source code but having a license to use it. You can easily get in trouble with them if you'll distribute your non-trival modifications otherwise.

[superkuh]

Only if you involve money. If you don't it's pretty safe.