TEMPEST [1] Is a US Gov't program revolving around, essentially, emissions security. It has been known for decades that you can spy on someone using e.g. the EM emissions from their monitor/VGA cable. This is a tweet apparently highlighting a method of using deep learning to make recovered images easier to read. Not many details. This seems more related to image processing than to security, based on my first impressions.
[1] https://en.wikipedia.org/wiki/Tempest_%28codename%29?useskin...