SQLite
The database inside nearly every phone, small enough to carry in a pocket.
D. Richard Hipp's database sits inside phones and browsers. The authors gave the library to the public domain.
D. Richard Hipp
Public domain
In 2000 D. Richard Hipp wanted a database that lived in the same process as the program, in an ordinary file, with no administrator in the loop. SQLite was the answer, and the authors gave it to the public domain.
The bars are the opening of sqlite3_exec, the call you hand a handle, a string of SQL, and a callback. It prepares the statement, steps through the rows, and calls back once per row. Nearly every phone and browser carries a copy and never says so.