For well behaved Linux application, you’d expect them to maintain their stuff in 3 different locations:
~/.config
to store user configuration files - i.e. “user has set up stuff”.~/.cache
to store temporary data - i.e. “created for now, but if its gone and I have to recreate it, nobody cares”~/.local/share
to store stateful data - i.e. “things I’ve done that I’m going to be needing for my next run”.
I’m guessing you are looking for the third thing - the Akregator stateful data, i.e. RSS downloads and stuff like that, will probably be in ~/.local/share/akregator
or something similar.