STEPS TO REPRODUCE:

1. Use a build with "browser.urlbar.quantumbar" set to true (in my case a nightly starting 2019-05-03 on Linux).

2. Open about:preferences, go to "Privacy & Security" section, and uncheck "Bookmarks" in the "Address Bar" ("When using the address bar, suggest") section.

3. Create a bookmark with a tag named "test".

4. Type "* test" in the URL bar.

EXPECTED RESULTS: The bookmark is suggested, in spite of the setting from step 2, since this is an explicit search on bookmarks.

ACTUAL RESULTS: The bookmark is not suggested.

ADDITIONAL INFORMATION: Toggling "browser.urlbar.quantumbar" to false restores the expected behavior.

On Mac, for some reason, this regressed way back in April before quantumbar was enabled; I am still trying to pin down that regression.

Ah, the Mac thing was to do with the testing setup and force-downgraded profiles: An April 11 build works with a current profile, but an April 12 build does not (!).

So all that's going on here is the quantumbar bit.

Probably the filtering code in the providers manager is not overriding the bookmarks pref with the bookmarks restriction token. If nobody looks into this earlier, I may have a look tomorrow.

https://hg.mozilla.org/mozilla-central/rev/763d3da98117

Reproduced the regression on 68.0a1 20190506130308, then verified it as fixed on:

             Ubuntu 16.04 && Windows 10 && Mac 10.14:
                                          beta            68.0b7 2019-06-03
                                          nightly        69.0a1 2019-06-06