/usr/share/postgresql/9.3/extension/plsh--unpackaged--1.sql is in postgresql-9.3-plsh 1.20130823-1git1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | ALTER EXTENSION plsh ADD PROCEDURAL LANGUAGE plsh;
ALTER EXTENSION plsh ADD FUNCTION plsh_handler();
ALTER EXTENSION plsh ADD FUNCTION plsh_validator(oid);
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