I also found https://www.madewithangular.com/#/categories/google. It's a far far far cry from OPs original assertion that 3/4 apps in Google are made of angular.

The Angular team has said over 70% of web apps at Google use Angular, but I can't recall what talks they have said that at off the top of my head. Various members of the Angular team have told me this directy as well, and are pretty open about that fact in general.

One told me about the broken release at one point last year bringing Google to a halt until that got fixed, since Google runs off of the master branch of Angular. Google has a lot of apps, most of them internal (I have seen some external ones too, such as a Nexus site in the past, and Google Domains. Google App Engine and Adwords also use it, as given in talks in the past - the Angular team is grouped under the Ads group within Google). Your original question for proof was completely misguided when accounting for that - examples of external facing apps does not confirm or deny percentage, it was a poorly conceived attack.

Certain apps like Gmail/Inbox go through very long development cycles and have specialized requirements. An Angular team member has explained to me that sometimes some teams think they can do better with vanilla JS - none of the popular web frameworks really met Google's perf/business requirements for those behemoth apps, although with the way Angular 2 is shaping, it likely will hit the bar (the Angular team has managed to get a hello world app smaller than a react-based one, and this is before they extract out the template compiler to allow tree shaking of that for builds - very impressive perf numbers were also thrown at Google I/O last week). Google has a lot of resources they can throw at big consumer facing apps, so they can build homespun frameworks if they need to (for big sites like YouTube, Inbox, Calendar, etc.).

I should also detail that I'm not someone unknowledgable about Angular and how it is used - I am one of the biggest Angular experts outside of Google, a core maintainer of one of the three most largest third party Angular libraries & involved in another top three most used third party library (UI Bootstrap and UI Router, respectively) and a contributor to many projects across the ecosystem. I am very aware of all of the things that are Angular's strengths, and its shortcomings (especially 1, and 2 to a lesser degree...but nobody is really an expert at 2 yet, excepting maybe Tobias Bosch on the Angular 2 team with his crazy work on it).

@Bahamut, thanks for your perspective! fwiw, we are big angular users as well. I was only questioning it's usage in Google. I think I now know that it's used a lot more than I thought inside google.

I was going to say "If it's not ad or search, Google will have no trouble killing it off", but this makes it a little bit business critical to Google.

I'd only start worrying if they move that away from Angular.