Safari logs to ~/Library/Containers/com.apple.Safari/Data/Library/Logs/ on macOS. 1 other macOS log location is recorded below.
Paths are printed exactly as Safari writes them. Environment variables like %LOCALAPPDATA% and $XDG_STATE_HOME are never expanded, so a path can be pasted straight into a shell. Where a path differs between installer types or shipping flavours, each one is racked as its own card below - why that happens.