/usr/src/glibc/debian/debhelper.in/glibc-doc.manpages is in eglibc-source 2.19-0ubuntu6.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | debian/local/manpages/pthread_atfork.3
debian/local/manpages/pthread_condattr_init.3
debian/local/manpages/pthread_cond_init.3
debian/local/manpages/pthread_key_create.3
debian/local/manpages/pthread_mutexattr_init.3
debian/local/manpages/pthread_mutexattr_setkind_np.3
debian/local/manpages/pthread_mutex_init.3
debian/local/manpages/pthread_once.3
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