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
in the OSF FAQ.
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.