postinst is in vala-terminal 1.3-6build1.
This file is a maintainer script. It is executed when installing (*inst) or removing (*rm) the package.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12  | #!/bin/sh -e
set -e
if [ "$1" = "configure" ]; then
	update-alternatives --install /usr/bin/x-terminal-emulator \
	x-terminal-emulator /usr/bin/vala-terminal 50 \
	--slave /usr/share/man/man1/x-terminal-emulator.1.gz \
	x-terminal-emulator.1.gz /usr/share/man/man1/vala-terminal.1.gz
fi
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