Since Version Firefox 71 (Win10 64bit) autofill for bookmarks in addressbar is broken
Steps to reproduce:

1. fresh profile
2. In preferences disable "entries from histry" and "open tabs" (only let enable "entries from bookmarks")
3. add a new (unvisited) bookmark for example https://example.com/blablabla/)
4. type exa in adressbar

In Firefox 70 it make a suggestion for autocomplete for maindomain https://example.com
In Firefox 71 it make no suggestion for autocomplete for maindomain

I can confirm this, running Firefox 71 on Arch Linux. Autocompletion of domains from bookmarks is broken since 71.

However, in rare cases it seems to work: I exported all my bookmarks via backup, deleted the bookmarks in Firefox and re-imported from the backup. After a restart, the autocompletion of domains worked for a bit and then suddenly stopped working again.

Hello Team,
I've check this issue in 73.0a1 (2019-12-13) (64-bit) in windows 10 Nightly latest developer channel, but I can not replicate your issue in that. I think it is resolved in latest version.

I'm trying with version 71, will update you soon.

Thanks,
Bhargav Desai

Hello Team,
I've check this issue in version 71 (64-bit) in windows 10 , I can confirm this , Autocompletion of main domains from bookmarks is broken.

However , it work for some domain like reddit, youtube, instagram.

Thanks,
Bhargav Desai