App Monitoring
Reconnaissance
Also: recon, probing
The mapping step before an attack: finding what a target runs, exposes and forgets.
In more detail
Typical recon requests ask for /.env, /.git/config, backup files and admin paths. Most return nothing, but one hit can hand over credentials. Recon on its own is not a breach, but it shows an attacker is looking and tells you which files to double-check are not served.