This is a simple character vector. It contains the identification name of the active workspace. If a new name is assigned, that name becomes the identification name of the active workspace, provided that it is a correctly formed name.
See Workspaces for workspace naming conventions.
It is useful, though not essential, to associate workspaces with a specific directory in order to distinguish workspaces from other files.
The value of ⎕WSID in a clear workspace is 'CLEAR WS'.
⎕WSID
CLEAR WS
⎕WSID←'ws/mywork (UNIX)
⎕WSID←'B:\WS\MYWORK' (Windows)