When adding an application to an application group, add a long notes section to annotate the addition. Will allow a quick view on a specific entry within an app group/policy for an admin to include why something was added for future quick reference. For instance, an internal ticket number, a url for where an executable was downloaded from, etc. This way you don't have to clog up the description field with too much information and can keep that one concise.
Annotations for saving policies are good, but not great for historical quick reference on individual items within a policy. Having this notes field added as a column when viewing the application groups would be nice as well to have a singular view without having to click into each individual app.
Suggestion for location (see attached screenshots):
1. Below the description field when adding a new application
2. In the additional actions (3 dots button) on right side of the application after the app was added to the group.