The pref was added in bug 1570674 as an off-by-default toggle for a
session-scoped "Not Now" button on the Web Notifications permission prompt,
and has shipped false ever since. It is not enabled by any in-tree config and
is not controlled remotely, so the button is never shown to users.
Remove the pref, the notNowEnabled getter and the action it gated, and the
now-unused webNotifications.notNow strings. The notification prompt now
exposes a single, persistent "Always Block" secondary action.
Differential Revision: https://phabricator.services.mozilla.com/D310815
Emma Zuehlcke
c8d17ec75e