Firefox: https://blog.mozilla.org/futurereleases/2017/07/25/firefox-r... and https://developer.mozilla.org/en-US/docs/Plugins/Roadmap Google: https://www.blog.google/products/chrome/saying-goodbye-flash... and https://sites.google.com/a/chromium.org/dev/flash-roadmap Microsoft (Edge+IE): https://blogs.windows.com/msedgedev/2017/07/25/flash-on-wind...
*: That is, one that isn't just a reskin of another browser on the list.
Of course that describes what they are doing now, not their plans. Which is not surprising, because Apple never says anything about plans, as a matter of corporate policy...
That being said, while Apple hasn't explicitly said they plan to remove Flash from desktop Safari, they've implicitly signalled it -- they've already got features in place which make it often only load on demand.