From path's package docs:

Package path implements utility routines for manipulating slash-separated paths.

The path package should only be used for paths separated by forward slashes, such as the paths in URLs. This package does not deal with Windows paths with drive letters or backslashes; to manipulate operating system paths, use the path/filepath package.

IMO the documentation is clear and it already explicitly mentions Windows. What else would you like to see on this docs?

As noted above, its behavior is clearly documented to be platform independent which is necessary for safely manipulating non filesystem paths like URLs.

Ack, my bad.
Instead of reading the path packages overview at the top, I just read the documentation for Base()

Related Issues

• path: Split and Base functions do not handle Windows file paths #51951 (closed)
• path.Base doesn't work for Windows paths #57649 (closed)
• path.Base() does not split path properly on Windows 10 #14763 (closed)
• path.Base and path.Split do not properly split the file name on Windows as documented #49745 (closed)
• path.Dir() does not work on Windows #44302 (closed)
• path/filepath: EvalSymlinks is broken for relative paths on Windows #16793 (closed)

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}