Documentation on what triggers app restarts in Azure?

I'm in the process of upgrading some Azure function apps and I need to implement some application settings. The Portal UI says that changes to application settings will restart the application, but I don't see evidence of this in the Activity Logs of the app. The only entry I see is a 'Update Website' operation. So, now I begin to doubt what is really happening.

Is there documentation anywhere that is the source of truth?

Refer this document that states that the Application will restart when the app settings is applied:-

> - Changes to function app settings require your function app to be restarted.

Whenever you upgrade your application settings your Web app is restarted its similar to your IIS server where any change made in the application restarts the entire host in in order for those changes to get reflected in the web app. If the web app is not restarted the application settings does not apply. As some settings. Example- Adding WEBSITE_RUN_FROM_PACKAGE=1 allows the function trigger deployed as zip to run from the zip package without any warnings. In order to upgrade these changes in the function app or web app it is restarted once.

I tried adding WEBSITE_RUN_FROM_PACKAGE=1 setting in the Function app and it got restarted like below:-

Settings updated like below:-

Warning that states that the app will be re started :-

Update website setting logs is added in the Activity Logs refer below:-