In https://gitlab.com/lilypond/lilypond/-/merge_requests/1714 I suggest that we prefer luatex for building the documentation. What do people think?
The main advantage of using luatex is complete microtype support; this was activated recently in `texinfo.tex`, and XeTeX doesn't support it in its entirety, lacking font expansion. The microtype feature yields (a) less underfull lines (i.e., less lines with overly large inter-word spaces), (b) less hyphenation, and (c) a better 'grayness' of the pages, thus increasing legibility. While (c) is not a big issue with technical documentation, (a) has quite an impact IMHO, and (b) is valuable since it is always a good thing to avoid hyphenation with keywords and the like because there might be misunderstandings whether the hyphen is part of the keyword or due to the line break. Note also that documentation formatted with luatex has slightly less pages, but this is rather insignificant. Attached you can find an example that demonstrates (a), taken from the MR. You can read more about microtype principles in the documentation of the LaTeX 'microtype' package, of which `texinfo.tex` supports a small subset of the most important features. https://ctan.math.illinois.edu/macros/latex/contrib/microtype/microtype.pdf Werner