[debacle]

That user is using PEAR, which is the old shitty PHP "CPAN"

That's the reason for the huge memory usage. We're slowly moving away from PEAR, but since it works for now not everyone has/will transition.

Edit: I should also point out that there are a few packages that almost everyone uses (PHPMD, PHPCS, phpUnit) that are still mostly pulled from PEAR, though I think phpUnit has a composer option.

[ErrantX]

PHPUnit stopped updating PEAR in April, and actively destroyed PHPUnit on their PEAR repo at the start of this month (i.e. a patch version update that consisted just of a bash script printing a migration message...).