A container format for programs, similar to Flatpak and Appimage. Snaps were developed by Canonical, and while they're technically an open standard, the only place to get them is from Canonical themselves, so it's sort of a walled-garden thing like phone app stores. Snaps tend to be slower than native packages, and Ubuntu installs the snap version of things by default.
Mint is extremely similar to (and based on) Ubuntu, but with snaps gutted out. There are other differences, but that's the biggest one
That Google search will likely get you results related to multimedia formats, like ogg, webm, and matroska.
The more useful query would be 'containerized software packaging'. https://en.m.wikipedia.org/wiki/Snap_(software) is the link for snaps though, and it should be easy to find other containerized formats from there, Flatpak is probably in the 'see also' section
I don't like Snaps either, but it isn't a that big of a deal. Ubuntu is still vastly more private than Windows. I do prefer Fedora much more because it actually sandboxes system services with SELinux polices. Snap creates a better sandbox for applications than Flatpak, but it is slower to launch applications, depends on AppArmor (which is less secure than SELinux), and uses hard coded package repo (centralized design).
The comment I replied to wasn't comparing Ubuntu vs. Windows though, it was Ubuntu vs. Mint.
If my options were Ubuntu, Windows, and Mac, I'd go with Ubuntu, no question. But the nice thing about Linux is that there are a billion options, I can use what I like, other people can use what they like, and we can all play nice together and even contribute to the same codebase half the time.
I've tried Fedora-- every time I install a new machine, I end up trying several distros before inevitably landing on something with apt. I started on Ubuntu 15ish years ago, and run Debian on anything headless, I just can't get used to other package managers
Cinnamon with Wayland is still in testing. X11/X.Org is unmaintained software and is less secure than Wayland. GNOME is the only desktop at the moment that actually protects the screen from arbitrary recording by applications. Just food for thought.
Honestly, if you're happy with Ubuntu, don't worry about what other people think. A lot of the (valid) complains of Ubuntu require research to understand why to be outraged.
I personally only use immutable now (bazite, aurora and steam OS) and I wouldn't have it any other way now.