

I’m not sure if I understand what you’re talking about exactly. With root I can access all files on my device (including /data/data, where app internal files are kept) and I can give permission to apps to access all files too, it they ask for it. Not that I’d want that, because it’s way safer to keep user data in /storage/emulated/0 and give read permissions on file or folder level (like /Pictures for a gallery app, or just the picture I want to share for a social media app).
If you want to share data between apps, the easiest way would be to give them access to the same folder in user space. That isn’t OS maker’s generosity, that’s basic security controls.
Yeah, I had some webpages archived and tried to use javascript to clean them up, but I ended up parsing it as xml through Powershell instead. I’ve done something with Python and BeautifulSoup too, a long time ago. Both much easier than JS, but somehow JS is designed to work with web pages? Make it make sense.