Somewhat tangential, but from what I can see, the idea that "the blood of the covenant..." is the full version of the saying is a fairly modern invention.
I have bad memories of Netscape 4 and IE4 (I think those were the versions) which both allowed invalid HTML but had different rules for doing it. Accidentally missed off a closing table tag once, and one browser displayed the remainder of the page, but the other didn't.
Dictionaries - at least the ones I checked - mark the "very good" meaning of "egregious" as archaic. I'm only aware of the "very bad" meaning (in UK English), and was quite surprised, when studying maths, to learn of Gauss's "Theorema Egregium", and that the word could have positive connations.
On the ZX Spectrum, numeric values were saved as both text, and in a five-byte floating point format. So making lines shorter often involved using keywords to avoid that: NOT PI, SGN PI, VAL "2" etc.
"The thing to point out about that story is that there is no need for burden of proof on a colourful anecdote where we’re quite upfront about our own reservations about whether to take it seriously."
Just wanted to call out a couple of moments where this manual is far better than it needs to be, considering the target audience.
(from page 130) a description of calculating how long your ZX Spectrum has been powered on includes a discussion of the problem of a race condition when the counter ticks over
(from page 117) a program illustrating that the RND function uses a pseudo-random number generator
