What is a provisioning profile?
A provisioning profile is a small file, issued by Apple, that ties together an app's bundle ID, the certificate that signed it and what the app is allowed to do. An iPhone checks the profile before it opens an app that didn't come from the App Store. Development profiles also list the exact devices the app may run on.
More about Provisioning profile
Profiles expire: one made with a free Apple ID lasts 7 days, and a paid developer's development profile lasts a year. When a profile runs out, the app stops opening until it is signed again with a fresh one. Managing profiles by hand is one of the fiddliest parts of iOS development.
Provisioning profile with Borel
Borel Companion takes care of this when it puts an app on your iPhone: it signs the app with your Apple ID, and it signs it again for a fresh 7 days while it runs. For the App Store, Borel signs the build on its own Mac with your App Store Connect key.
Related terms
Make your iPhone app in Borel
Describe it in your own words. Borel writes it in Swift, builds it on its own Mac and puts it on your iPhone.