Did you Bitcoin Core had an alert system where developers could send messages to users? This was added by Satoshi after the inflation bug in August 2010 They could send a 256 bytes message to your node, like in the picture. image Satoshi, Gavin and theymos were the 3 known people to have access to the trigerring key. It was speculated Mark Karpeles(Mt. Gox CEO) had one. The only one to trigger these alerts was Gavin. image Even though it could only send a text message that was sent to your node, it was still dangerous. Some rogue actor could ask people to update to a bad client, and claim a vulnerability. Because of this it was completely removed in 2016, and the private key was made public. image
Most people know the 1st Bitcoin TX from Satoshi to Hal, in block 170. But did you know the 2nd TXs we know Satoshi made to someone was to Dustin Trammell in block 524 for 25 BTC. Cryptographically proven by Dustin. image However between the TX in Block 170 to Hal until the one shown above, we can see there were 7 other transactions made. Looking at how the funds flowed, it seems Satoshi was making test payments to hiself. image
Did you know Satoshi wanted to remove the beta-status of the Bitcoin client in 2010? Jumping from version 0.3 to 1.3. But people objected. This stuck up to September 2021, when we switched from Bitcoin Core version 0.21.0 to Bitcoin Core 22.0 image