There are not many pre-installed apps on the L5, but they all come from the regular PureOS repository, where every package is Free and Open Source software. You can uninstall anything you want, even the phone dialer, or install other packages that have been adapted to the screen size, from PureOS or any other GNU+Linux package repository you want to add.* (Some will work out of the box, some may work after tweaking them a bit, and some may not work because of different architecture or because they haven’t been adapted to the screen size.)
You don’t have to worry about anything pre-installed or anything that you install yourself, unless you go looking for some software from a sketchy source.
*Conflicts could arise from some repositories you try to combine with the PureOS repository.