There are two editions of Backupery for Slack app: Personal and Workspace.
If the Backupery for Slack Personal or Backupery for Slack Workspace is installed, a workspace owner and other members are not explicitly notified, however, any user can see the installed application if the following steps are performed:
- Click Apps on the bottom left:
- 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, all the members of the channel can see that the application was added: