The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/f7783aa80e8a3bf24c824efd925d9d7b1505b21d

commit f7783aa80e8a3bf24c824efd925d9d7b1505b21d
Author: dominickn <dominickn@chromium.org>
Date: Mon Apr 10 10:48:37 2017

Update the app banner action button to display "add" by default.

A/B testing revealed that "Add" had a better CTR than either "Add to
home screen" or "Install" in the banner. This CL updates the banner to
use the "Add" string in place of the current "Add to home screen".

The menu item string is left unchanged as the full "Add to home screen"
had the best CTR in A/B testing there.

BUG= 709866 

Review-Url: https://codereview.chromium.org/2806213002
Cr-Commit-Position: refs/heads/master@{#463217}

[modify] https://crrev.com/f7783aa80e8a3bf24c824efd925d9d7b1505b21d/chrome/browser/banners/app_banner_settings_helper.cc

I still see the 'Add to Homescreen' banner in 59.0.3068.1. Tested with pwa.rocks .

Thanks for pinging. There is an accompanying server-side Finch change that needs to roll out so that official builds see this.