Users in China trying to access GitHub.com were getting warning messages about invalid SSL certificates. The evidence indicates that this was caused by a man-in-the-middle attack. A week prior to this event, GitHub was completely blocked in China. But only a couple of days later, full access to the website was restored. This followed unusually public protest that may have forced authorities to rethink their decision. GitHub may just be too important to block because it seems that the authorities have backed off from blocking the website completely.”]
Source: https://en.greatfire.org/blog/2013/jan/china-github-and-man-middle