The PreTeXt Guide

We are careful about which LaTeX packages we use, trying to stick with well-established packages with active maintainers. But it can be useful to have a record of exactly which packagees are in play, and better still, which versions of those packages are being used. So you can use a publication entry to request loading the snapshot⁵ package, which will then automatically generate such a record into a <job>.dep file. See Subsection 44.3.11 for details on electing this feature.

If you suspect some packages are not playing well with each other, this record might be helpful for debugging this (rare) situation. It can aslo be useful if you wish to have a perfect archive of how some publication was produced. See the package documentation for more on the format and use.