It's hard to get excited now days when a company makes a move that sounds amazing on paper. Especially when looking at chromium which being open sourced is great, but then with Google having so much influence over it and chromium browsers having such huge market share it makes you wonder if that was always the initial intended goal they had from the get go even if it took decades.
Being open source doesn't make something not susceptible to suddenly finding itself held captive by corporate decisions if a majority of development and compatability is now hugely dependent on it. It would be hard to not wonder what their actual angle is.