Yes, they do.
I think it’s mostly (depending in the specific Version/OS) about 10 minutes default. For example, the Google Clock app lets you change the “silce after” option, with the default being 10 minutes.
Edit: I’ve tried to look for your specific alarm app but couldn’t find anything online (and I don’t want to download it just for testing), but maybe you could just download it wherever you are right now and search of there is a default option or test it?
Schau dir mal Proxigram an, ich denke das ist so ziemlich genau das was du suchst.