/usr/share/initramfs-tools
Directories:

• /usr/share/initramfs-tools/hooks
• /usr/share/initramfs-tools/conf-hooks.d
• /usr/share
• /usr/share/initramfs-tools/scripts
• /usr/share/initramfs-tools/conf.d
• /usr/share/initramfs-tools/modules.d

Files:

• modules
• hook-functions
• init