gentoo-overlay/sys-apps/microcode-data/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
<herd>base-system</herd>
<use>
	<flag name='initramfs'>install a small initramfs for use with CONFIG_MICROCODE_EARLY</flag>
	<flag name='monolithic'>install the large text microcode.dat (used by older kernels via microcode_ctl)</flag>
	<flag name='split-ucode'>install the split binary ucode files (used by the kernel directly)</flag>
</use>
</pkgmetadata>