The search field can be populated through a URL query parameter when the page is opened via context menu "View Saved Logins" or autocomplete's "View Saved Logins".

https://hg.mozilla.org/mozilla-central/rev/f5b8f8b18666
https://hg.mozilla.org/mozilla-central/rev/3034b68282fa
https://hg.mozilla.org/mozilla-central/rev/807c329de7ea
https://hg.mozilla.org/mozilla-central/rev/46fc2a3d94d1

Can you provide some details on how this implementation should be verified correctly? Thanks.

To test this bug, go to about:config and set signon.management.page.enabled=true and also set signon.management.overrideURI=about:logins

Then go to bugzilla.mozilla.org and attempt to log in
Click in the username field and a drop-down should appear to Browse for logins
Click on the button and about:logins should open with the search filter showing bugzilla.mozilla.org

I don't think I could validate it in Windows 10 and Nightly v69.0a1 (2019-06-12).
My steps:

1. Opened browser with a newly created profile.
2. Go to about:config and

• set:
  signon.management.page.enabled=true
• create:
  signon.management.overrideURI=about:logins

3. Go to bugzilla.mozilla.org

4. Click "Log In"
   -> Login form appears as a drop-down.

5. Click inside the "email" field.
   -> Nothing happens <-

6. Log in and save a set of credentials

7. Log out

8. Click "Log In"
   -> Login form appears as a drop-down and the Password Manager drops down under the "Email field"
   -> "about:logins" did not open with search filter showing bugzilla.mozilla.org <-

9. Click on the "View Saved Logins" button from the Password Manager drop-down.
   -> about:logins page is now displayed as Firefox Lockwise, but a filter showing bugzilla.mozilla.org is still not displayed.

Am I verifying correctly? Thanks.

Sorry, I gave you a wrong instruction in comment 9. You will need to set signon.management.overrideURI=about:logins?filter=%DOMAIN%

The "?filter=%DOMAIN%" part at the end is required. Otherwise your steps sound correct.

With the newly given instructions, I have retaken the steps in comment 10. The difference is that when the user clicks on the "View Saved Logins" from the Password Manager drop-down (step 9), the about:logins page is displayed as Firefox Lockwise and a search is initiated for "bugzilla.mozilla.org".
The page's link address is "about:logins?filter=bugzilla.mozilla.org"

Does this behavior validate the intended implementation?

Behavior verified in Nightly v69.0a1 (2019-06-18). Thanks.

Yes, that validates the intended implementation.

Based on the above, I will mark this bug as verified in Nightly v69.0a1 (2019-06-18). Thanks.