A binary package built with xbps is a normal tar(1) archive, compressed
with bzip2 and has the following structure:

	/
	/usr ------|
	/var ------| => Package structure that will be installed.
	/etc ------|
	...
	/var/cache/xbps/metadata/$pkgname
	/var/cache/xbps/metadata/$pkgname/flist
	/var/cache/xbps/metadata/$pkgname/props.plist
	/var/cache/xbps/metadata/$pkgname/postpre-action

Metadata info is stored in the "/var/cache/xbps/metadata/$pkgname"
directory and two files will be always be present: flist and props.plist.

The flist file contains the list of files that the package will
install. The props.plist file is a proplib(3) property list and
has the following structure:

<dict>
	<key>pkgname</key>
	<string>foo</string>

	<key>version</key>
	<string>3.40</string>

	<key>maintainer</key>
	<string>The Master BOFH <bofh@baobab.org> </string>

	<key>short_desc</key>
	<string>Foo is a virtual package</string>

	<key>long_desc</key>
	<string>
 Foo is a virtual package to show how the metadata props.plist file works
 with xbps handling binary packages.</string>

	<key>architecture</key>
	<string>x86_64</string>

	<key>installed_size</key>
	<integer>500000</integer>

	<key>configuration_files</key>
	<array>
		<string>/etc/foo.conf</string>
		...
	</array>
	<key>run_depends</key>
	<array>
		<string>bofh-2.0</string>
		<string>blab-1.1</string>
		...
	</array>
	...
</dict>

The prepost-action is an executable script/command that allows you to
trigger any action at pre/post installation/removal of the binary
package. If return value is not 0, the package won't be registered into
the database.

The package's dictionary will also be written into the repository's package
index file, that describes information about a binary package on it.
See the BINPKG_REPOSITORY file for more info about repositories.