The Quick Action Bar menu that appears at the bottom of Firefox Preview for Android with Bookmark, Share, Read and open in App has been removed, the items have been moved to the three-dot menu in the latest Nightly version.
Recently we’ve covered that Mozilla has made Firefox Preview 3.0 download available, the release notes itself confirm QAB has been replaced by browser menu. While the change was not landed in the first beta yet, but it can be spotted in the Firefox Preview Nightly version for sure.
FYI, the first beta for Firefox Preview 3.0 has enabled enhanced tracking protection for all users and adds notifications support for downloads.
Coming to the subject in the article, Firefox Preview displays Quick Action Bar (QAB) at the bottom of the web page, you can slide up from the bottom navigation bar to see it. It allows us to share, bookmark, read and open the current article link in the supported app, if installed on the device.
Mozilla has removed this in the Nightly version of Firefox Preview and moved the options to the vertical three-dot menu. You can notice share and bookmark (star) icons as well as Reading view toggle and Open in App menu item in the main menu.