If you are wanting to see what you have installed to decide what you want to install later on you can open a terminal and use pacman.
pacman -Q will list everything on your system, which is not really helpful
pacman -Qe will list everything that you have explicitly installed adding a lower-case q to the end will get rid of version numbers
pacman -Qm will list what you have installed from the AUR
pacman -Qn will list what is from repositories
pacman -Qdt will list orphaned dependencies, these may or may not be programs you want to keep.
these commands may help you with deciding what programs you may want to put back on your system after you do a fresh minimalist install.
Even more helpful!
Does pacman -Qe = (pacman -Qm + pacman -Qn), so to speak?
It does look line it
Is there any way of seeing what I actually installed, rather than what I installed plus the dependencies that that needed?
e.g pacman -Qe gives me, amongst so many others, spectre-meltdown-checker which must have been installed with something else as I have no idea what it does let alone remember installing it
and it includes things like manjaro-settings-manager which came with manjaro
I guess my interpretation of explicitly installed is wrong