How does this work for users that are not using a desktop OS/browser? Is there a mobile app that does this and holds the content for local viewing?

On Android, there are a number of solutions, like NewPipe (YT client) and Seal (downloader).

All of the above will be detected and blocked by YouTube.

This would mean YouTube will have to break compatibility with countless outdated Android / iOS apps, Smart TVs and other devices. Not gonna happen anytime soon.

> YouTube will have to break compatibility with countless outdated Android / iOS apps, Smart TVs and other devices

Minus smart TVs, this seems like the point of the policy change. (And even on the TVs, if they're watching without paying while blocking ads, that's purely a cost centre.)

If we enter Twitter as evidence into the record of yanking the cord on 3rd party apps getting a free ride off your company's hard work, then maybe Google has decided the negatives do not outweigh the positives.

You aren’t understanding. They can’t change the old unpublished APIs because it will break the old devices. We use those to get the videos without the ads.

What reason does YT have to NOT make changes that prevent those devices from working? Is there an avenue for these 3rd party devices to pay YT for their services? If these apps/devices are making a buck off of YT rent free, then they should be able to yank the cord whenever they want.

Your comment reads as if you feel that YT has some sort of obligation to continue letting 3rd parties make money from the work of YT without any compensation.

Device manufacturers not just use some private API or SDKs without making deal with Google. Except might be for Chinese noname brands from AliExpress.

All device manufacturers do have agreements with Google about support for their devices and such agreements can very well be for 10+ years or even for lifetime of the devices.

PS: Actually 10 years ago when Windows Phone was a thing Microsoft has tried to make their own YouTube client without agreement with Google and it was killed by Google almost immediately.

Google just dropped all third-party Google Home device support, leaving people with e.g. Lenovo Smart Displays twisting in the wind. It wouldn't be out of character for them to "alter the deal" w.r.t. all those old smart TVs and such.

Newpipe.

I’ve used it with Plex, works fine

Yeah, yt-dlp is great. It happily grabs stuff Invidious can't play. Indispensable IMO.