browser.onboarding.disabled = false
browser.onboarding.hidden = false
browser.onboarding.tour-set = "new" // for new user tour, or "update" for update user tour

And make sure the value of browser.onboarding.tourset-verion and browser.onboarding.seen-tourset-verion are the same.

How to show the onboarding notification

Besides above settings, notification will wait 5 minutes before showing the first notification on a new profile or the updated user profile (to not put too much information to the user at once).

To manually remove the mute duration, set pref browser.onboarding.notification.mute-duration-on-first-session-ms to 0 and notification will be shown at the next time you open about:home or about:newtab.

How to show the snippets

Snippets (the remote notification that handled by activity stream) will only be shown after onboarding notifications are all done. You can set preference browser.onboarding.notification.finished to true to disable onboarding notification and accept snippets right away.

Architecture

Everytime about:home or about:newtab page is opened, onboarding overlay is injected into that page.

OnboardingTourType.jsm will check the onboarding tour type (currently support new and update). Then in onboarding.js, All tours are defined inside of onboardingTourset dictionary. getTourIDList function will load tours from proper preferences. (Check How to change the order of tours section for more detail).

When user clicks the action button in each tour, We use UITour to highlight the correspondent browser UI element. The UITour client is bundled in onboarding addon via jar.mn.

Landing rules

We would apply some rules:

To avoid conflict with the origin page, all styles and ids should be formatted as onboarding-*.
For consistency and easier filtering, all strings in locales should be formatted as onboarding.*.
For consistency, all related preferences should be formatted as browser.onboarding.*.
For accessibility, images that are for presentation only should have role="presentation" attribute.

How to change the order of tours

Edit browser/app/profile/firefox.js and modify browser.onboarding.newtour for the new user tour or browser.onboarding.updatetour for the update user tour. You can change the tour list and the order by concate tourIds with , sign. You can find available tourId from onboardingTourset in onboarding.js.

How to pump tour set version after update tours

The tourset version is used to track the last major tourset change version. The tourset-version pref store the major tourset version (ex: 1) but not the current browser version. When browser update to the next version (ex: 58, 59) the tourset pref is still 1 if we didn't do any major tourset update.

Once the tour set version is updated (ex: 2), onboarding overlay should show the update tour to the updated user (ex: update from v56 -> v57), even when user has watched the previous tours or preferred to hide the previous tours.

Edit browser/app/profile/firefox.js and set browser.onboarding.tourset-version as [tourset version] (in integer format).

For example, if we update the tourset in v60 and decide to show all update users the tour, we set browser.onboarding.tourset-version as 3.