site level, but optional.
Properties which can also appear in public key files.
+ (named by `peer-keys' key to secnet sites closure.)
These are acceptable to make-secnet-sites only at
site level. See also `Site long-term keys' in NOTES.
Not yet suported in make-secnet-sites.
pkg GROUPIDHEX
+ pkgf GROUPIDHEX
Specifies the key group id for subsequent keys.
+ pkgf indicates a fallback group.
May be repeated (with different id values).
If not specified, 00000000.
Not yet suported in make-secnet-sites.