thinkpad-tech-tree.txt is intended to be a plaintext map of all ThinkPad-brand laptops and tablets sold by IBM and Lenovo from 1992 to the present year. It was inspired by the "tech trees" found in some games. The "tree" is currently incomplete for years 1993-1995 and is missing the ThinkPad i-Series. Recent work has been slower since I am less familiar with the pre-2005 models. Your contributions can help complete the "tree"!
You may notice that this file includes a significant number of spaces. If you want to edit it, I recommend using a text editor that can convert between spaces and tabs, such as Notepad++.
If your preferred text editor wraps lines and ruins the formatting of
thinkpad-tech-tree.txt, I recommend you look into my other project, thinkpad-tech-tree-tall and download the file there. That file only includes ThinkPads from 2005 to 2019, but in short time, older models will be added to it as well.