Yes, it's being released soon. We got sidetracked by high priority work.

GrapheneOS has support for sandboxed Android Auto. If people use it via wired Android Auto then the only special permission which needs to be granted via our Android Auto permission toggles is more USB access. Certain apps including most navigation apps integrate specific support for Android Auto and forward content to it when using it. It sees what's forwarded to it but that doesn't mean anything invasive is happening in practice. It doesn't send it anywhere else.

As you already said, using an alternative OS won't significantly improve security because it won't provide missing the many missing firmware, kernel, driver and HAL patches in practice. Using LineageOS would mostly mean continuing to get AOSP userspace patches after end-of-life. The firmware, kernel, driver and HAL patches are very important and receiving only the AOSP userspace patches doesn't really achieve all that much when many major Linux kernel holes aren't patched.

Fairphone 3 has an end-of-life Linux 4.9 kernel which hasn't been receiving updates for multiple years. They weren't shipping kernel updates even while they were available. Fairphone 4 and Fairphone 5 also have end-of-life kernels. Fairphone 6 kernel isn't end-of-life yet but they're not shipping the updates. This is a massive security problem for every Fairphone and it's very easy to exploit them due to it. There are publicly available exploits usable for those kernels.

If your app has a hard dependency on Play services then there's not much point in publishing it via Accrescent. If you can avoid a hard dependency on Play services then publishing it via Accrescent would allow people to use it without involving Google Play. Accrescent also distributes the releases you sign rather than releases signed by Google, but it's a game not handling sensitive data so that isn't a big deal. GrapheneOS users can install it from the Play Store perfectly fine now.

If you want to make your app your app easily available outside of the Play Store, you can apply to publish it via Accrescent which is a Play Store alternative available in the GrapheneOS App Store. It's currently in Alpha and you need to apply to publish apps through it. See https://accrescent.app/ for more information.

Your app is easily available to GrapheneOS users regardless especially now that you fixed the Play Integrity API store listing issue but you can support an alternative.

Their app works fine on GrapheneOS.

GrapheneOS doesn't use microG and microG requires privileged integration into the OS to function which isn't included. We have our own compatibility layer due to the privacy, security and compatibility limitations of microG resulting in it not meeting our requirements.

They weren't saying their app didn't work on GrapheneOS but rather users couldn't install via the sandboxed Play Store which they've fixed in their store listing.

Their app works fine on GrapheneOS and there's no reason it would require microG. GrapheneOS provides much broader app compatibility than operating systems using microG.

The only form of Google Play available for GrapheneOS is sandboxed Google Play which runs as regular apps with no special access. The issue they were describing is that their app couldn't be installed through the sandboxed Play Store on GrapheneOS because they had the store listing set to disallow non-Google-certified devices and operating systems. Users could still install it via Aurora Store.

No, that's not what microG provides. It's a reimplementation of Google service middleware sitting between the Google libraries used by apps and Google services. Those apps are still using Google's libraries and services. It doesn't avoid services such as Firebase Cloud Messaging being a privacy issue but rather provides a reimplementation of one part of the implementation. The client and server side portion is the same.

https://grapheneos.social/@GrapheneOS/116462439837570993

Based on your other replies in the thread, you've resolved the issue already. Google misrepresents the feature you enabled as a security feature when what it actually does is disallowing any device or OS not licensing Google Mobile Services including integrating Google's Chrome web browser, etc. from installing your app. GrapheneOS users can work around it by using another Play Store frontend as opposed to the sandboxed Play Store but it's much better if apps avoid using that setting.