Urlbar suggetions box broken when keyword.enabled is true starting in 68.14.8b
Make a new profile in Mypal 68.14.8b or later (including 74.1.0)
Open a new tab and start typing in the urlbar, the suggestions box shows fine. Go to about:config and set keyword.enabled to true. Open a new tab and start typing in the urlbar, the suggestions box is gone.
The suggestions box is buggy in these later releases. It can still show or work in some cases with keyword.enabled, however it's always broken in the case you're most likely to use it (a new tab)
Seems it broken after the moving xul stuff, don't know when shall look it, certainly not soon. You care then may try fix yourself.
You apply all your changes in one batch, I can't go through and look and see if anything looks related and revert a specific commit, or even bisect because it's all the changes in one big commit.
Maybe I could look into what keyword.enabled does and trace it, but I just don't feel like it for now.
For the beginning you may look at the error, anyway no one else cares.