The only file with this name is located in: ProjectName\Saved\Config\WindowsEditor
(NOT A ProjectName\Config!!!)
And copying the Plugin list from there will not help in any way, because there is not a complete list of active plugins (I don’t know why) this method does not work.
UPD: The list of plugins is stored in Nameproject/Name project.uproject, you need to open it as a text file.