Error in 9.6 documentation? checkpoint_flush_after

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/9.6/runtime-config-wal.html
Description:

https://www.postgresql.org/docs/9.6/runtime-config-wal.html
19.5.2

checkpoint_flush_after (integer)

    Whenever more than checkpoint_flush_after bytes have been written while
performing a checkpoint, attempt to force the OS to issue these writes to
the ...

bytes or pages?tgresql.conf says pages