I only managed to get half the solution to last weeks challenge.
Finding the first half of the solution was pretty straight-forward.
In the File system view (or via your image mounting directory traversal of choice) navigate to \var\log\apt.
Here we find the history.log file which keeps track of applications installed via apt.
If you scroll to the end of the log you can see that a lot of packages were installed or upgraded on 2017-11-08. From there on we have no (logged) activity until 2019-10-07 when php [Flag] is installed.
Part 2 I’m afraid eluded me. I’m looking forward to seeing the other write-ups to see the solve for the Why?