I know someone else reported this as well, but I can't find the topic, so here's a repost. If you install PM6 (and PM+) fresh on a Mac Mojave system, it asks to control the computer (see screenshot).
While it looks like you can safely deny this, it's still weird that it asks for control in the first place. What's even stranger still is that the access request is not done as PM6, but as PM+ (that is, there will be an entry named PhotoMechanic Plus in the Privacy|Accessibility list). You can easily verify this by going to the Privacy tab in the Security & Privacy System Preferences. The application list will show you an entry for PM+, not PM6.
You can repeat triggering the request easily as well: simply delete the entry for PM+ in the list (with PM closed) and then restart PM. Likely the dialog box will get hidden by the program window, but if you move that away, you'll see the dialog again.