/usr/lib/mysql-testsuite/r/have_utf16.require is in mysql-testsuite-5.6 5.6.16-1~exp1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | Collation Charset Id Default Compiled Sortlen
utf16_general_ci utf16 54 Yes Yes 1
|