/usr/share/binfmts/cli is in mono-runtime 4.2.1.102+dfsg2-7ubuntu4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | package mono-runtime
detector /usr/lib/cli/binfmt-detector-cli
interpreter /usr/bin/cli
magic MZ
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