[rusk]

It needs an apostrophe then it makes more sense “Windows’ Subsystem for Linux”

It is a Windows Subsystem, that caters to running Linux.

It’s a functional title not an architectural one.

[1718627440]

Subsystem isn't used as a random English word here, "Windows Subsystem" is already a fixed term. So you wouldn't introduce a possessive relation into the term when using it.

[rusk]

Indeed, I was trying to make it easier for you.

[Jenk]

Or a colon:

    Windows Subsystem for: Linux