Settings → Virus scanning: switch it on, point it at a ClamAV daemon,
choose the two policies, and see how many files are waiting, in
quarantine, or were let through unscanned. Switching it on with no
address is refused rather than saved and left inert.
The Test button is three answers, not one. Unreachable is obvious.
Reachable but detecting nothing is the failure that looks like success
— empty or broken virus definitions — so the test sends the EICAR
string and reports "it found the test file", never "it did not
complain". The string is assembled at runtime so no checkout contains
it: antivirus software on a developer's machine quarantines files that
do.
"Scan existing files" queues the library that predates scanning,
through the hourly command so no request is held open, paced by a
setting so it does not starve today's uploads.
Where the environment names a scanner, the connection and the on/off
switch leave the screen and scanning cannot be turned off — the same
managed shape the CAPTCHA screen has. The two policies stay editable,
because what to do with a file nobody could scan is a decision about
somebody's own files.
ignacionelson