tab reordering would be possible but the shift-clicking on the tab group would have to be some other mechanism like a context menu action or something along those lines.
Oh, apologies, I meant the _user_ would be responsible for shift-clicking and tearing off those tabs; I haven't ever seen an extension that was able to do those kind of wholistic browser operations
ah i see... yeah an extension could theoretically do it but it would be along the lines of right click on a tab and then select a context menu action that the extension installs that would then do something like "break this group off into a new window"... fairly trivial to implement but I don't think it exists right now.