@Dunbrokin If you want to report a bug, your first port of call would be the link in the Support section in the listing of the app in the Open Store. Sometimes it links to an email address. But more often it links to an issue tracker on github, gitlab or some other online version control provider. In the latter cases, you will probabl need to have an account on the platform before being able to report your issue.

If it is just some question you have about an app, then I guess posting a query on the forums would be as good a place as any.