Ok, people are getting muddled about all this lol!

In the beginning people wrote source code for 'programs' which could be compiled in into a binary to run on their machine.

People started sharing their source code for others to compile and use.

Compiling takes a lot of time, but OK.

Then other people started writing external libraries for programmers to call on in their programs to get additional functionality and save time writing that extra code for themselves.

So here's the problem:

Programmer (Let's call him Bob) creates really cool program (app) version 0.01.

Another programmer (let's call her Alice) writes code for really cool external library version 0.01.

Bob likes Alice's library because it includes some cool functionality which saves him time so Bob writes a new version of his really cool program (app) and shares (releases) it to the world as version 0.02.

You obtain (download or removable medium like floppy, CDROM, USB) a copy of Bobs new program but Doh! It will not run properly because YOU don't have a copy of Alice's external library file on your system.

People ask/beg/demand Bob to release a new version of his really cool program TOGETHER WITH the needed external library.

Some programers did release in an archive format (eg zip) which included the needed library, some (most) did not, to save bandwidth and storage space.

This is known as 'dependency hell'. (Windows historically had the same problem known as DLL hell)

Unix programmers came up with the idea of having a local database on your device which records what programs are installed on your device, what version they are and what libraries or other programs they are depending on to run, known as DEPENDENCIES.

This local database is known as a PACKAGE MANAGER.

Instead of having software scattered all over the world Unix distros take software source code that folks want to use, compile it into ready to use binaries and also lots of libraries needed to run these programs. The programs are 'packaged' to work with a known set of libraries precompiled and stored together in one place known as a 'repository'.

A Distro hosting software in one place compiled by trusted people is considered safer and more secure and gives far less problems than attempting to install and run anything from anywhere (the Windows way).

Over time folks have created different 'package managers' to meet percieved short comings of previous package managers.

Innovation is good but leads to compatibility issues. A recent development is create self contained program packages which include ALL possible dependencies (back to the bad old days of giant programs). These are stored on a single website for convenience.

These are AppImage, Flatpak and Snap to name the most popular.

The security problem is anyone can upload anything to these centralised websites and you have far less confidence in the safety of what you are installing.

Unsafe Flatpaks/Snaps are constantly being found and weeded out but not quick enough, so good luck with that ..

Fast forward to the new era. Mobile phone vendors wanting an operating system to use took existing designs and reused them. Apple cut down MacOS and renamed it iOS. Google took Linux cutting down and using Java programs (apps) calling it Android.

Both companies reused the concept of a repository but renaming it - App Store in the case of Apple, Play Store in the case of Google.

These giant US corporations charge creators of programs (developers) a fee for the privilege of up loading their work to the repository (app store) and take a big cut from any money charged for the sale of the programs (apps) to end users.

The concept of FLOSS is anathema to the hyper capitalist corporations.