User talk:FBXL5
Something has gone wrong with the Artwork Assembly page
You have worked on the Artwork Assembly page and sadly you edit does not make sense.
First of all the Assembly folder still exists in the source code: https://github.com/FreeCAD/FreeCAD/tree/master/src/Mod/Assembly
Second it is rather the Asm3 folder that does not exist! https://github.com/FreeCAD/FreeCAD/tree/master/src/Mod
I see not other solution than to undo your edit.