I have Aquamacs as follows:
Aquamacs 3.5 GNU Emacs 188.8.131.52 (x86_64-apple-darwin16.7.0, NS appkit-1504.83 Version 10.12.6 (Build 16G2016))
dated 2019-08-18 rev. 70b7398da506a9a53867909fa12e5cb3a07ba5c9
Copyright (C) 2017 Free Software Foundation, Inc.
Running on Catalina, 10.15.2
I opened a file in Aquamacs, and stumbled on the "services" menu on the tab for the file buffer. One of the options is "Show in Finder."
This does not work for me. When I select it, Aquamacs does bring the Finder into focus, but it just brings up the last accessed Finder window, and does not open the folder containing the file from Aquamacs.
I have tried this on multiple files and got the same results.
I tried to test it on Aquamacs without customizations and ... found no "Services" menu item on buffer tabs. So I don't know if this is just me, but if it is, I have no idea what customization would give me a (non-functioning) "Services" submenu.