Where is a Macbook's MAC / ethernet address stored in the file system?

Macbook was stolen, want MAC / ethernet address from TimeMachine backup for police report, where is it in the file system? An earlier (c. 2015) post referred to a location in ~/Library/ with sub-folder ByHosts, but no such file exists under Macintosh\ HD/Library/ in my backup. (Does "~" point somewhere else?)