publicid_fpi.identifier.txt

                                  ┏━━━━━━━━━━━━━━━━━━┓
                                  ┃   PUBLICID_FPI   ┃
                                  ┗━━━━━━━━━━━━━━━━━━┛

STANDARDS ==>                     #  - SGML
                                  #  - RFC 3151 (for URN notation)

GOAL ==>                          #Identifier describing identity and metadata, used in SGML.
                                  #Not meant to be resolved to a location.

FORMAT ==>                        #PREFIX//OWNER//CLASS DESCRIPTION//LANG[//VERSION]
                                  #  - PREFIX: ISO (standard), + (registered), - (not registered)
                                  #  - OWNER
                                  #     - can be IDN DOMAIN, in which case can be considered registered
                                  #  - DESCRIPTION
                                  #Same charset as SGML attribute values but:
                                  #  - whitespaces -> single space
                                  #  - no leading|trailing whitespaces

URN ==>                           #urn:PUBLICID 
                                  #  - replace // by :
                                  #  - replace space by +
                                  #  - percent-encode