I’ve got various things that have licenses, and I like knowing how things are licensed, so it is useful for me to mark the things.
I’m gonna start using the SPDX short-form identifiers.
Quick aside, here is all the license data (including JSON) in a git mirror: mirror/license-list-data - license-list-data - allthe.codes
I don’t like SPDX for most of it’s purpose. Every time I read the website I can’t help but think this is a way for companies to sue people. So I don’t think it should be used as a shortcode link to a file as a header in each source file. I just think they compiled a sane list of short IDs to use, and I’m gonna.
The whole list is longer than I thought (381!) so I’ll leave it here, at the end. The meta data field copying is an array, will have one or more of the following identifiers. 
- 0BSD
- AAL
- Abstyles
- Adobe-2006
- Adobe-Glyph
- ADSL
- AFL-1.1
- AFL-1.2
- AFL-2.0
- AFL-2.1
- AFL-3.0
- Afmparse
- AGPL-1.0-only
- AGPL-1.0-or-later
- AGPL-3.0-only
- AGPL-3.0-or-later
- Aladdin
- AMDPLPA
- AML
- AMPAS
- ANTLR-PD
- Apache-1.0
- Apache-1.1
- Apache-2.0
- APAFML
- APL-1.0
- APSL-1.0
- APSL-1.1
- APSL-1.2
- APSL-2.0
- Artistic-1.0
- Artistic-1.0-cl8
- Artistic-1.0-Perl
- Artistic-2.0
- Bahyph
- Barr
- Beerware
- BitTorrent-1.0
- BitTorrent-1.1
- blessing
- BlueOak-1.0.0
- Borceux
- BSD-1-Clause
- BSD-2-Clause
- BSD-2-Clause-FreeBSD
- BSD-2-Clause-NetBSD
- BSD-2-Clause-Patent
- BSD-3-Clause
- BSD-3-Clause-Attribution
- BSD-3-Clause-Clear
- BSD-3-Clause-LBNL
- BSD-3-Clause-No-Nuclear-License
- BSD-3-Clause-No-Nuclear-License-2014
- BSD-3-Clause-No-Nuclear-Warranty
- BSD-3-Clause-Open-MPI
- BSD-4-Clause
- BSD-4-Clause-UC
- BSD-Protection
- BSD-Source-Code
- BSL-1.0
- bzip2-1.0.5
- bzip2-1.0.6
- Caldera
- CATOSL-1.1
- CC-BY-1.0
- CC-BY-2.0
- CC-BY-2.5
- CC-BY-3.0
- CC-BY-4.0
- CC-BY-NC-1.0
- CC-BY-NC-2.0
- CC-BY-NC-2.5
- CC-BY-NC-3.0
- CC-BY-NC-4.0
- CC-BY-NC-ND-1.0
- CC-BY-NC-ND-2.0
- CC-BY-NC-ND-2.5
- CC-BY-NC-ND-3.0
- CC-BY-NC-ND-4.0
- CC-BY-NC-SA-1.0
- CC-BY-NC-SA-2.0
- CC-BY-NC-SA-2.5
- CC-BY-NC-SA-3.0
- CC-BY-NC-SA-4.0
- CC-BY-ND-1.0
- CC-BY-ND-2.0
- CC-BY-ND-2.5
- CC-BY-ND-3.0
- CC-BY-ND-4.0
- CC-BY-SA-1.0
- CC-BY-SA-2.0
- CC-BY-SA-2.5
- CC-BY-SA-3.0
- CC-BY-SA-4.0
- CC-PDDC
- CC0-1.0
- CDDL-1.0
- CDDL-1.1
- CDLA-Permissive-1.0
- CDLA-Sharing-1.0
- CECILL-1.0
- CECILL-1.1
- CECILL-2.0
- CECILL-2.1
- CECILL-B
- CECILL-C
- CERN-OHL-1.1
- CERN-OHL-1.2
- ClArtistic
- CNRI-Jython
- CNRI-Python
- CNRI-Python-GPL-Compatible
- Condor-1.1
- copyleft-next-0.3.0
- copyleft-next-0.3.1
- CPAL-1.0
- CPL-1.0
- CPOL-1.02
- Crossword
- CrystalStacker
- CUA-OPL-1.0
- Cube
- curl
- D-FSL-1.0
- diffmark
- DOC
- Dotseqn
- DSDP
- dvipdfm
- ECL-1.0
- ECL-2.0
- EFL-1.0
- EFL-2.0
- eGenix
- Entessa
- EPL-1.0
- EPL-2.0
- ErlPL-1.1
- etalab-2.0
- EUDatagrid
- EUPL-1.0
- EUPL-1.1
- EUPL-1.2
- Eurosym
- Fair
- Frameworx-1.0
- FreeImage
- FSFAP
- FSFUL
- FSFULLR
- FTL
- GFDL-1.1-only
- GFDL-1.1-or-later
- GFDL-1.2-only
- GFDL-1.2-or-later
- GFDL-1.3-only
- GFDL-1.3-or-later
- Giftware
- GL2PS
- Glide
- Glulxe
- gnuplot
- GPL-1.0-only
- GPL-1.0-or-later
- GPL-2.0-only
- GPL-2.0-or-later
- GPL-3.0-only
- GPL-3.0-or-later
- gSOAP-1.3b
- HaskellReport
- HPND
- HPND-sell-variant
- IBM-pibs
- ICU
- IJG
- ImageMagick
- iMatix
- Imlib2
- Info-ZIP
- Intel
- Intel-ACPI
- Interbase-1.0
- IPA
- IPL-1.0
- ISC
- JasPer-2.0
- JPNIC
- JSON
- LAL-1.2
- LAL-1.3
- Latex2e
- Leptonica
- LGPL-2.0-only
- LGPL-2.0-or-later
- LGPL-2.1-only
- LGPL-2.1-or-later
- LGPL-3.0-only
- LGPL-3.0-or-later
- LGPLLR
- Libpng
- libpng-2.0
- libselinux-1.0
- libtiff
- LiLiQ-P-1.1
- LiLiQ-R-1.1
- LiLiQ-Rplus-1.1
- Linux-OpenIB
- LPL-1.0
- LPL-1.02
- LPPL-1.0
- LPPL-1.1
- LPPL-1.2
- LPPL-1.3a
- LPPL-1.3c
- MakeIndex
- MirOS
- MIT
- MIT-0
- MIT-advertising
- MIT-CMU
- MIT-enna
- MIT-feh
- MITNFA
- Motosoto
- mpich2
- MPL-1.0
- MPL-1.1
- MPL-2.0
- MPL-2.0-no-copyleft-exception
- MS-PL
- MS-RL
- MTLL
- Version 1
- Multics
- Mup
- NASA-1.3
- Naumen
- NBPL-1.0
- NCSA
- Net-SNMP
- NetCDF
- Newsletr
- NGPL
- NLOD-1.0
- NLPL
- Nokia
- NOSL
- Noweb
- NPL-1.0
- NPL-1.1
- NPOSL-3.0
- NRL
- NTP
- NTP-0
- OCCT-PL
- OCLC-2.0
- ODbL-1.0
- ODC-By-1.0
- OFL-1.0
- OFL-1.0-no-RFN
- OFL-1.0-RFN
- OFL-1.1
- OFL-1.1-no-RFN
- OFL-1.1-RFN
- OGL-Canada-2.0
- OGL-UK-1.0
- OGL-UK-2.0
- OGL-UK-3.0
- OGTSL
- OLDAP-1.1
- OLDAP-1.2
- OLDAP-1.3
- OLDAP-1.4
- OLDAP-2.0
- OLDAP-2.0.1
- OLDAP-2.1
- OLDAP-2.2
- OLDAP-2.2.1
- OLDAP-2.2.2
- OLDAP-2.3
- OLDAP-2.4
- OLDAP-2.5
- OLDAP-2.6
- OLDAP-2.7
- OLDAP-2.8
- OML
- OpenSSL
- OPL-1.0
- OSET-PL-2.1
- OSL-1.0
- OSL-1.1
- OSL-2.0
- OSL-2.1
- OSL-3.0
- Parity-6.0.0
- PDDL-1.0
- PHP-3.0
- PHP-3.01
- Plexus
- PostgreSQL
- PSF-2.0
- psfrag
- psutils
- Python-2.0
- Qhull
- QPL-1.0
- Rdisc
- RHeCos-1.1
- RPL-1.1
- RPL-1.5
- RPSL-1.0
- RSA-MD
- RSCPL
- Ruby
- SAX-PD
- Saxpath
- SCEA
- Sendmail
- Sendmail-8.23
- SGI-B-1.0
- SGI-B-1.1
- SGI-B-2.0
- SHL-0.5
- Version 0.51
- SimPL-2.0
- SISSL
- SISSL-1.2
- Sleepycat
- SMLNJ
- SMPPL
- SNIA
- Spencer-86
- Spencer-94
- Spencer-99
- SPL-1.0
- SSH-OpenSSH
- SSH-short
- v 1
- SugarCRM-1.1.3
- SWL
- TAPR-OHL-1.0
- TCL
- TCP-wrappers
- TMate
- TORQUE-1.1
- TOSL
- TU-Berlin-1.0
- TU-Berlin-2.0
- UCL-1.0
- Unicode-DFS-2015
- Unicode-DFS-2016
- Unicode-TOU
- Unlicense
- UPL-1.0
- Vim
- VOSTROM
- VSL-1.0
- W3C
- W3C-19980720
- W3C-20150513
- Watcom-1.0
- Wsuipa
- WTFPL
- X11
- Xerox
- XFree86-1.1
- xinetd
- Xnet
- xpp
- XSkat
- YPL-1.0
- YPL-1.1
- Zed
- Zend-2.0
- Zimbra-1.3
- Zimbra-1.4
- Zlib
- zlib-acknowledgement
- ZPL-1.1
- ZPL-2.0
- ZPL-2.1