Thanks. But I don't see any code for the actual mobile app only for the website.
or
https://nojs.openmonero.com => click the 'Open source code attribute' inside 'Why use our service'
Discussion
For added security, the mobile app is not native (PWA) to have isolation from the filesystem. The web app is built with reactjs (selfhosting with docker possible), while the nojs version is based on php (codeigniter 4 framework)
On the "Get our mobile app!" banner at the bottom of the website there is a direct download for an apk. Is there a repo for that?
Yes, check the openmonero-reactjs repo hosted on forgeo. Link is in the popup if you click the "Open source arttribute" inside "Why use our service". Its the same code and can be self-hosted over tor hidden service.
Build from source
Recommended node version (use nvm): v14.21.3
sudo apt install torsocks
torsocks git clone http://rf5cqoxqlitdx4umuce5dgihjzabql4hs3zjkvs3em7xzjfa5yyhkeqd.onion/om/openmonero-reactjs.git
cd openmonero-reactjs
npm install
npm start