I have installed Sitecore in Azure PaaS. In App_Config\include folder I can see there are a lot of config files name started with "zzz". Can anyone please tell me what is these files are for? Are those any configs creating by any job?
There are probably hundreds of examples where using the z prefix can be seen. This is a convention followed to ensure that the patch is applied last.
Before Sitecore 9, using a folder or a file prefix with z was the best way to get your changes applied in the desired order.
After Sitecore 9, there was introduced a new feature to apply configuration changes based on the role of the instance running.
The best approach is to use a folder to contain your patches and only use the z notation when you are finding it difficult to override an existing setting.
A good example might be a pre-existing configuration is contained in a folder called Foundation/C and you initially stored your override in a folder called Foundation/A. You then proceed to rename the A folder to Z. Now everything in your z folder will be applied after the C folder.