Anyone can start using Linux as part of their product or environment, and so today there are literally billions of resulting end users effectively using Linux systems with uncountable configurations.

Unless you want at least every developer and system administrator in the world to subscribe to that mailing list and regularly read it, I don’t know how this can really solve the problem.

Add to that the fact that the classification of a “feature” is rather fuzzy…

There are already announcements and discussions through various channels, but at the end you can never be sure. Fortunately systems don’t have to always be updated immediately (aside from for security concerns).

I see the workflow something like this:

1) Some old feature, like an obscure filesystem, is causing some pain to maintain.

2) Therefore people suggest to add it to the phase-out list.

3) After some discussion it is decided it is a worthy candidate for removal and so it is placed on the phase-out list.

4) Some people starts subscribing, but not too much. Turns out it's some obscure distribution for an Atari emulator.

5) Time pass and years later these people have moved on to better things, they reply to the reminder email saying it's fine now.

6) Feature gets removed safely.

Windows and macOS solves this by the much hated "user tracking" (aka analytics).

I'm not sure if they "solve" this. In this current case, this was solved by working with the person that need the feature, rather than just tracking their usage of said feature.

"The" person. How do we know there's only one? Well, in this case, the story was sexy enough to be transmitted all the way to HN. Also two decades have passed. But in general, the 'post removal notice on some list and hope people notice' isn't a good method.

Apple solves this by removing whatever it is they don't like anymore and expecting developers to get on with migrating to the new thing that replaces it.

Microsoft hasn't solved it, Windows is drowning in its own moat.