I've been use MATE almost since it came out.
IIRC I used to use a series of mouse clicks to determine the file name
{including path} of the current icon.
On my current systems {one Stretch, one Buster} if I:
1. right click on the Launcher
2. select properties
3. left click on the current icon
I get a "Select Custom Icon" menu. In it I can select a directory to
search and it will display a list of available icons in that directory.
But I need to know the complete path to the current icon.
I can get the desired information by opening the launcher with a text
editor. {I want a "mouse click" method to obtain the information as I'm
setting up a system for a very novice user.}
Suggestions?
TIA