Lenovo ThinkPads have a very long history. Even the naming scheme of the business laptop line has a history, as it is more than 10 years old in its current iteration. Its roots are even older and date back to the IBM ThinkPad days. Now, it has apparently run its course, as the ThinkPad L13 does not adhere to the known naming scheme – and it seems like its not going to be the only upcoming Lenovo ThinkPad model.
https://www.notebookcheck.net/Leak-Lenovo-ThinkPad-E14-previews-new-naming-scheme-for-well-known-business-laptop-brand.434397.0.html