[kazinator]

Dummy empty files such as .keepme were used in CVS repositories for exactly the same purpose, and probably other version controls systems long before Git existed.

The Peter Cederqvist manual recommended the practice.

Here is a 1993 dated copy someone left hosted:

https://www.astro.princeton.edu/~rhl/cvs/cvs.html

The paragraph which recommends the .keepme files is:

https://www.astro.princeton.edu/~rhl/cvs/cvs.html#SEC63

"if you want an empty directory then put a dummy file (for example `.keepme') in it to prevent `-P' from removing it."