/usr/share/fish/completions/psub.fish is in fish-common 2.4.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | complete -c psub -s h -l help --description "Display help and exit"
complete -c psub -s f -l file --description "Communicate using a regular file, not a named pipe"
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