Documentation
I'm using Python 3.9 and building some GUI for a hobby project of mine on NixOS/Linux.

The Python documentation on tkinter explains the packer.

However, going through TkDocs Tutorial on geometry concept there is an upgrade box saying:

We'll go into more detail in a later chapter, but grid was introduced several years after Tk became popular. Before that, an older geometry manager named pack was most commonly used. It's equally powerful but much harder to use, making it onerous to create layouts that look appealing today. Unfortunately, much of the example Tk code and documentation out there uses pack instead of grid (a good clue to how current it is). The widespread use of pack is a leading reason that so many Tk user interfaces look terrible. Start new code with grid, and upgrade old code when you can.

In order to not shy away people, it might make sense to update the documentation code to use the newer grid geometry manager.