proph No, as both Hulk and abcZ mention, GrapheneOS is based directly on AOSP and develops their own featureset on top of it, we do not cherry pick from any other OS.
The purpose of GrapheneOS is that it's a hardened OS improving privacy and security from the bottom up. CalyxOS isn't hardened and is heavily based on LineageOS. It's more similar to Lineage than GrapheneOS.
Previously several Calyx and Lineage developers had taken code from GrapheneOS, stripped away attribution and presented it as their own. This includes the implementation of A/B updates in the update client and a dozen other changes.
We don't rely on them. LineageOS doesn't preserve the security model and rolls many parts of it back but that's not how we do things. Which in turn means other projects based on them claiming to be private/secure actually just provide a heavily branded, barely different variant of LineageOS with a bunch of marketing claims. Their focus is bundling apps and branding. Neither provide security updates reliably, so on what basis can they claim it's private/secure and still how could we ever be compared or thought to be based on it?
We ONLY build on top of AOSP. GrapheneOS is a hardened OS with substantially improved privacy / security grapheneos.org/features based on latest release of Android 13 with full security updates, security model intact and near 100% app compatibility. GrapheneOS and LineageOS/Lineage based OSes are very different kinds of projects. Meaning if you said you've installed LineageOS, or some other insecure aftermarket OS based on it to someone who installed our hardened OS substantially improving their privacy and security would be backwards if that was your focus.
I don't want this to seem overly blunt but just wanted to dispel beyond doubt for anyone else that there is any comparison between them. I appreciate that if you don't know you need to ask questions, no harm no foul as they say. Take care.