Tap "Add to Home Screen" on a web page and it gets its own icon on your phone. Open it and it feels like an app, and sometimes it opens even with no internet.
PWA is the name for this kind of page. It stands for "progressive web app": it is a web page at heart that has gradually grown a few app-like abilities.
Like a parcel locker at the supermarket door: no private warehouse built for you, yet what you need is there whenever you want.
Step 4 is like copying frequently dialed numbers into a notebook: when your phone is dead and the contacts are out of reach, the notebook is still there.
Also, some deep features of the phone are out of a web page's reach and only real apps can use them. iPhones are especially strict, which is why big companies' main products are mostly still apps.
Subscribing to websites like a newspaper: new posts arrive in one mailbox, you choose what to follow, and nothing is pushed on you.
The world's shared address book: you remember names, machines use numbers, and DNS translates. How it looks things up, and why sites sometimes won't open.
Every submitted change is checked automatically before it goes live. What CI and a runner are, why they start on boot, and what they can't do.
The finished video is like a PDF; the project is the PowerPoint you can still edit. What's inside, what export does, why keep the project, and a common trap.