A 5-character GUID is assigned to every user,
project, component, and file on OSF and forms the basis for the service's
URL scheme. For example the GUID for a project accessible at
https://osf.io/ezum7 is simply ezum7
. You can learn more about GUIDs
here.
An important detail is that files and directories are handled internally on
OSF by another serviced called Waterbutler,
which uses 11-character identifiers. Although Waterbutler IDs are largely
hidden from users on https://osf.io, they represent the primary method for
identifying files/directories by the OSF API. In fact, files do not receive a
GUID until it is viewed directly on https://osf.io and directories never
receive a GUID. Therefore, osfr relies on Waterbutler IDs for files and
directories, and always includes them (rather than GUIDs) in osf_tbl_file
objects.