@mcc

Not sure if it helps, but:

"A" is "Firefox View" which was a failed project and is probably being sunset. Like you, though, I really like it. You can get to it via about:firefoxview, and you can pin that tab to have it available.
"B" is the "new and improved" Search and Manage Tabs flyout, which also has a link to Firefox View at the very bottom. It will also show things like Tab Groups (which I never really use) or other "smart tab" crap. You can move it from the main bar with Customize. I threw it in the overflow menu.

I also tend to use the URL shortcut of % to search open tabs, and ^ to search my history. (* lets you search bookmarks, if you ever wanted. Those are nice because they're all keyboard accessible.