[puzzlingcaptcha]

Few might remember that Alpine was originally based on Gentoo. You can still find some old references (like mkinitcpio hooks for fbsplash).

[klardotsh]

Possibly the biggest hint is /etc/apk/world, the "worldfile", or the list of explicitly installed packages. It's even the same verbiage Gentoo uses (albeit a different location - Gentoo stores it somewhere under /var)