I was about to install PixelFed, listed in Google Play as a 13-MB app, but it demanded to delete apps before I free 500 MB. Similar thing happens with F-Droid, although it gives less data. Why? Does it not, like Flatpak on PC, list dependencies? But that’s dumb; plus, no dependency for a browsing app may take 500 MB of space, and the demands aren’t getting smaller when more apps are on device.


Android apps don’t pull in dependencies like that. But even though it’s a 13 MB download, I see when installed it’s showing me it takes up 76 MB, before I’ve even opened it for the first time.
No, I don’t know why there is a discrepancy, nor why it told you 500 MB. But I do know the fancy new thing for apps is a split package, and usually apps require dynamic recompilation during installation, so that might be why they ask a safety margin of up to 500 MB. (But I agree it still seems high.)