Embrace. Microsux notices there is a software tool that is becoming very popular with people. The problem they have with it of course is it's not owned by them and it's also not part of their vision of how they want people to use computers. So they will (perhaps after failing to discredit the reputation of the tool) Embrace the tool, tell everyone they love it, love working with it, etc. Then they will...

Extend. Add features/plugins/whatever to extend the functionality of the tool a bit more in the direction of their vision. All proprietary extensions of course. Possibly they have bought ownership rights to the tool by now as well. They work to ensure people now rely on the modifications they made, then they...

Extinguish. They snap their fingers and snuff it out. They owned it so people who use it have no choice but to accept they can't use it any more. Then they tell everyone "Hey look, you should do your work this way instead with our other tool."

They're doing this with Linux right now. They used to say "Linux is a cancer" because it is not proprietary, it is free. Free to be modified, shared, used. Then they embraced it, then they extended it by creating the Windows Subsystem for Linux. This integrates a Linux environment directly into Windows so that developers who are used to using Linux can now use Linux inside the Windows OS. See where this is going?

This is why proprietary software is a bad thing. Look up what a copyleft license is.

One more thing: there is a difference between Free software and Open Source software. Open Source allows you to see the source code (before it is compiled into non-human-readable machine code which is what actually runs on the computer) so it can be inspected for bugs, malicious instructions/intent, etc, but it is NOT guaranteed to be free to modify, share, use, etc. Free software includes being open source because you cannot modify it without the source.

This is why the Open Source movement is another "false flag" as I call them because it confuses people away from the freedom that is necessary for people around the world to work together on making software better for everyone.