/usr/share/gocode/src/github.com/ugorji/go/codec/prebuild.go is in golang-github-ugorji-go-codec-dev 0.0~git20151130.0.357a44b-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | package codec
//go:generate bash prebuild.sh
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