I became aware of this while watching Professor Brailsford's interview with him (Computerphile channel): https://www.youtube.com/watch?v=GNyQxXw_oMQ

(Around 7-8 minute mark)

Update:

At 24-25 minute mark, he talks about the technologies he is inquiring to write his new book with (he mentions troff and groff).

He says he wanted to try "XeTeX" (which supports Unicode) but "...I was going to download it as an experiment and they wanted 5 gigabytes and 5 gigabytes at the particular boonies place I'm living would...mmm..not be finished yet!"

So there we go...We had the opportunity to read the mind of the developer of awk and unix and co-author of the literal "C Programming Language", confronting with the absolute state of the tooling of the modern world.

He can try "Tectonic" [0] - a modern XeTeX based TeX/LaTeX distribution that installs a minimum system and then downloads and installs dependencies on-demand. Tectonic is written in C and Rust [1].

[0] https://tectonic-typesetting.github.io/en-US/

[1] https://github.com/tectonic-typesetting/tectonic