Best Practice 30.17.1. Only Edit LaTeX Files Rarely.
We want to stress that the LaTeX file created by various conversions is mean to be an intermediate format. In other words, it is ephemeral. We try to make it clean and organized, but it is not the LaTeX a human would write. You might be able to recycle a paragraph or two in other documents you create without PreTeXt. But it is not meant to be stable or archival and no long-term use is supported in any way. In other words, it is not a supported output format, beyond compiling to a PDF without errors.
Having said all that, you may find it necessary to manually adjust a file to control widows or orphans, or maybe the placement of a graphics file, or similar adjustments. We view this as the final step before making a new edition, which might be a PDF that you submit to a print-on-demand service (Chapter 43). So this might be an annual exercise, at the most frequent.