Maybe I don't understand what this new tool was supposed to do.
Prior to upgrading
I am set for utf8 in the language file and complete and the database is set at utf8_general_ci
But emojis don't work.

I upgraded to 7.7.4 today and in re builders I find.
Update All Tables to UTF8mb4
Configuration settings indicate that you have aleady completed this action.

So I can't run the tool because it is disabled.
And emojis give me most times a
One emoji saved in black and white

Using the win key

One other note when attempting to search the language files for the typo for aleady in the control panel I get:
Parse error: syntax error, unexpected '<', expecting end of file in /home4/mysite/public_html/ub/languages/english/faq.php on line 46

But I did find it manually in languages/english/admin/rebuildcontent.php

Blue Man Group
There is no such thing as stupid questions. Just stupid answers