Synced Tabs: Allow opening multiple tabs in the background

[StentMan]

What is the user problem or growth opportunity you want to see solved?

I have a bunch of tabs open on my desktop. When I'm afk and have some time to read I'd like to open a few of them and read them. Today, I need, for every tab I'd like to open go through the pancake menu, pick sync tabs, click a tab - rinse repeat. I'm suggesting that while I'm at the Synced tab I'll be able to pick multiple tabs and open them, similar to what's already possible to perform when I want to open multiple bookmarks.

How do you know that this problem exists today? Why is this important?

It's not important, it'll just make using Firefox easier, make interactions more consistent (same as bookmarks).

Who will benefit from it?

anyone who uses the Synced tabs feature.

┆Issue is synchronized with this Jira Task

[chartmix]

This would be highly appreciated.
When I move to a new phone or want to switch devices it would make the process easier.

[issue-dispenser]

I just switched devices and this feature could have made transferring the opened tabs a lot less tedious.

Please also consider an action to "open all synced tabs from [device]" to facilitate transfer of Android -> Android open tabs while ignoring desktop tabs (issue #11404 with a device filter).

[jonalmeida]

Moved to bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1810784

Change performed by the Move to Bugzilla add-on.