gentoo-overlay/app-misc/skim/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
	<!-- maintainer-needed -->
	<use>
		<flag name="tmux">Install sk-tmux script to run skim in a tmux pane</flag>
		<flag name="vim">Install vim plugin for skim</flag>
	</use>
	<upstream>
		<remote-id type="github">lotabout/skim</remote-id>
		<changelog>https://github.com/lotabout/skim/blob/master/CHANGELOG.md</changelog>
	</upstream>
</pkgmetadata>