According to Wikipedia, it’s still based on Gentoo, it just uses Debian for running Linux applications in Crostini.

If this happens, I’d be interested in seeing how this effects ChromeOS. I don’t use it but my mom does.

Also, if you’re confused as to why ChromeOS would be effected, while it’s based on Gentoo Linux, ChromeOS uses a modified version of Chrome as it’s Desktop Environment.