Which version of Ubuntu? The last time I checked, --all was not enabled by default in Ubuntu? Can someone confirm if this is indeed true?
If this is indeed true, how do they achieve this? Do they modify git source code to achieve this?
Nevermind, I made a mistake and tested it on a repo where ---all would have little noticeable effect. It is indeed disabled by default.
That said, custom source edits are entirely possible. Canonical does keep their own repositories after all [1].
EDIT: Or not. It's off by default actually.