gentoo-overlay/dev-util/schroot/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
	<!-- maintainer-needed -->
	<use>
		<flag name="btrfs">Enable support for chroots using btrfs snapshots</flag>
		<flag name="dchroot">Enables the building of a wrapper named "dchroot", replacing <pkg>sys-apps/dchroot</pkg></flag>
		<flag name="lvm">Enable support for chroots using LVM snapshots</flag>
		<flag name="zfs">Enable support for chroots using ZFS shapshots/clones</flag>
	</use>
</pkgmetadata>