GNU: A Heuristic for Bad Cryptography
If you see the letters GNU in a systems design, and that system intersects with cryptography, I can almost guarantee that it will be badly designed to an alarming degree.
Delta Compression
A diff algorithm outputs the set of differences between two inputs. These algorithms are the basis of a number of commonly used developer tools. Yet understanding the inner workings of diff algorithms is rarely necessary to use said tools. Git is one example where a developer can read, commit, pull, and merge diffs without ever understanding the underlying diff algorithm. Having said that there is very limited knowledge on the subject across the developer community.
Source: The definitive, practical guide to diff algorithms and patch formats, an article by Tsviatko Yovtchev.
The Autumn Republic: Good
In the evening I finished The Autumn Republic, the final book in the Powder Mage Trilogy by Brian McClellan. I enjoyed the book a lot, but still consider the first in this series; Promise of Blood the best. It was a good read, with a very good ending. I do recommend this series.