Judy1(3) on Linux
The text fa8fbeecd0dc, as Debian 13 (Trixie), Debian 12 (Bookworm), Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie) shipped it.
C library for creating and accessing a dynamic array of bits, using any value of a word as an index.