Another tweet suggests that proposed rule available below, proposed on November 19, and seeking comments by December 19, 2018, is what Ken Harris was referring to
This proposed rule "seeks public comment on criteria for defining and identifying emerging technologies" which includes biotech, artificial intelligence and a dozen other high tech areas. There's no specific proposal but it could give the "Bureau of Industry and Security" the power to control export and transfer of emerging and foundational technologies. The request seems to recognize the complexity of doing this, it states:
Aside from the date comments are due I'm not sure what if anything in that tweet is different from the Oct 10 action. There is also nothing recent in any news outlets that I could find which also makes me think the tweet is just alarmist BS