At the moment, no there isn’t a special or sanctioned way to determine if you are running on DABL.
window.location is by far the most straightforward way to find out; you could use various APIs as documented on docs.projectdabl.com/api but I wouldn’t necessarily recommend that since window.location is such an easy and simple solution.
Just out of curiosity, what are you looking to do based on whether you are running in DABL or not?
Wouldn’t that be the case no matter where it is deployed if it’s a reference application? I think of “reference app” as “sample app”; anyone looking to use it for a real use case would certainly at least want to customize the appearance and make a few minor changes.
Couldn’t that limitation apply to other ledgers as well? I suppose I’m saying the warning should either be there as part of your app, or not—or potentially be a configuration option in the hands of the person deploying the software. Certainly it seems like this would be a legitimate warning to show during dev time on someone’s development laptop, which would also be a non-ideal platform for storing private health information.