Its Google as in the code was written by Google (AOSP). But the binary is built by themselves, on their build server (As with any other custom ROM).

It's like Chromium on Debian. It's Google code compiled by Debian

To be fair, it's tremendously difficult to even know what gets compiled in to the final package you get. Fun fact, Lineage, without GAPPS still phones home for network connection checks.

> Isn't it ironic that lineage is still basically Google?

Could you not say the same about any Android ROM?