The current Terminal app uses a Debian virtual machine image that is downloaded straight from Google. There are two issues with this, one being "Debian" and one being "Google". There seems to be some users asking for the feature to run a different distro, but the GrapheneOS team has been busy with other things. There was also the NestBox app by kdrag0n, but that has been broken for a while.
After some trials and errors, I found out that it is possible to build a third-party app that allows you to use a VM image provided by yourself. This opens up a lot of possibilities.
So I am making an app that does just this. A proof-of-concept version is up at:
https://github.com/outlawsanzhang/koiterminal
Currently, it is able to boot a modified version of Debian that is provided by the user, just to prove that this is possible on the official GrapheneOS system without root. There is also an upstreamable branch that can be contributed to GrapheneOS, in case it is useful when they are no longer busy and want to start "building on sand" (referring to the unstable ongoing development of the app in AOSP).
I will use this thread as a devlog for the app, at least initially. Next steps are going to be trying to solve the VPN blocking issue and making a custom image from scratch.
This app is still very very early in development, but I want to release it to gauge interest and get feedback from the community. Is this plan feasible or a doomed effort? Do people actually want to use something like this instead of Termux or the Debian terminal? Does using system APIs and installing apps compiled as a system component impact security? Will the app keep working for at least half a year until the next AOSP update? Feedback is appreciated as always.