Last time I opened Software Manager it said I had 9.13 Gb disk space remaining.
Today after a while I opened Software Manager. It took a while indeed updating the repos, but when finally finishing, Software Manager said I had 8.9 Gb disk space remaining! And even after rebooting! (Though I noted Software Manager opened much faster after reboot, probably since it didn't need to update everything again...).
I didn't install anything new nor created/copied any file in my hard disk on all this while, and even deleted all cookies on Firefox.
What's going on!?