Version 2 (issue #17) adds the optional derivations sidecar. The
field was added under a version bump rather than silently because
this document is read back by UGM.fromJSON, and a reader must be
able to tell "no derivations" from "written by a build that did not
know about them". A document with no version is the form every
build before 2 wrote; fromJSON reads it as 1 and still loads it.
Serialized UGM format for save/restore (T4).
Version 2 (issue #17) adds the optional
derivationssidecar. The field was added under a version bump rather than silently because this document is read back byUGM.fromJSON, and a reader must be able to tell "no derivations" from "written by a build that did not know about them". A document with noversionis the form every build before 2 wrote;fromJSONreads it as 1 and still loads it.