mdraw_text_per_char_extents(3m17n) on Linux
The text 8fb5fb09f965, as Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy) shipped it.
Compute the text dimensions of each character of M-text.