If the app is installed, a workspace owner and other members are not notified, however, any user can see the installed application if the following steps are performed:
- Click “Apps” on the bottom left:
2. Browse Apps box will be shown:
The application is shown here along with who and when installed it.
Please also note, that if you add Backupery for Slack Workspace application to a channel or DM, all the members of the channel or DM can see that the application was added: