The docker compose files of applications downloaded in CasaOS are stored in the following location on the current device.
/var/lib/casaos/apps
Also, if you have added tips to these apps, you can access the tip data under the name tips: in the docker-compose.yml file of the app under the apps folder.
For example use this command to get tips section for Jellyfin app:
sudo cat /var/lib/casaos/apps/jellyfin/docker-compose.yml | grep tips