Thomas A. Alspaugh
OSS (and Other) Licenses, §/¶/sentence/word‑numbered

The Open Source Initiative provides standard texts for each license it has certified as Open Source. However, because the licenses are organized and formatted in a variety of ways (and because a few licenses have apparent formatting problems), it is difficult to make an unambiguous reference to a section, paragraph, sentence, or word in a license.

§¶s markers and HTML ids

Here are a selection of prominent open-source software (OSS) licenses and a few others, with sections, paragraphs, sentences, and words numbered for unambiguous reference. The numbering has been done by a program, guided occasionally by me (see Mapping §¶s markup to a document).

Each sentence starts with a marker like


giving the section number (if any), the paragraph number within the section, and the sentence number within the paragraph. The example above identifies section 1, paragraph 2, sentence 3. Subsections and subparagraphs receive sub-numbers, like this example identifying section 1, subsection 2, paragraph 3, subparagraph 4, sentence 5:


and within sentence 5, an abbreviated marker (like all clause markers) for clause 1:


Each word in the licenses has been given its own HTML id based on its §-¶-sentence-word position. Hover the cursor over a word to see its HTML id and full §¶sw location. For example, this has HTML id 'S1p8s3w3' indicating it is section 1, paragraph 8, sentence 3, word 3 (hover the cursor over it to verify for yourself), and a hyperlink like this one can be set up to jump to that specific word.

Sections, paragraphs, and sentences have their own HTML ids that can be used to hyperlink to them. §1¶9ṣ2 Sentence ids are visible (like the one at the beginning of this sentence), and paragraph and section ids can be inferred from them; ṣ2.1 this sentence's id is S1¶9ṣ2, so this paragraph's id is S1p9 and this section's is S1. Hyperlinks can be set up to the sentence, paragraph, and section.

Where the license text gives section or list item numbers, or uses letters or Roman numerals, the §-¶-sentence numbers match them. If the section numbers begin at 0 rather than 1, and the §-¶-sentence numbers match this also.

document model

Figure 1. Model applied
to a document

A §¶s model of a document

Each document is modelled as a title, zero or more enumerated paragraphs, and zero or more enumerated sections. Each section is recursively modelled the same way, with a heading as its title and subsections as its sections. The recursion continues down as deep as HTML supports (h6). At this writing, the deepest level required by a license is the h5 level used in the Sun Community Source License (SCSL) v2.8.

Each paragraph comprises one or more sentences; each sentence comprises one or more words. A sentence is divided into clauses (for lack of a more widely-accepted term) at semicolons and colons, and at inline list item markers such as (i) or (1).

If needed for list items, the latter part of a paragraph may be divided into enumerated subparagraphs, and the latter part of each subparagraph into enumerated subsubparagraphs; the division points need not be between sentences. At this writing the deepest paragraph subdivisions are into subsubparagraphs. The LGPLv3.0 license, for example, utilizes subsubparagraphs in a nested list. Paragraphs are only divided into subparagraphs and subsubparagraphs if required for list elements.

If needed for list items, the latter part of a clause may be divided into enumerated subclauses. At this writing, for example, the MPL 1.1 license utilizes subclauses in a nested list. Clauses are only divided into subclauses if required for list elements.

Document title paragraph* h1-section*
h1-section heading paragraph* h2-section*
h2-section heading paragraph* h3-section*
h3-section heading paragraph* h4-section*
h4-section heading paragraph* h5-section*
h5-section heading paragraph* h6-section*
h6-section heading paragraph*
heading word+ [.?!]?
paragraph sentence+ subparagraph*
subparagraph sentence+ subsubparagraph*
subsubparagraph sentence+
sentence sentence-head clause* [.?!]
clause [:;] clause-head subclause*
sentence-head word+
clause-head word+
subclause word+

Grammar of §¶s model.
Commas, quotation marks, and other punctuation not affecting the markup may appear anywhere.

Exceptions to the model

The overwhelming majority of text in licenses has proved to fit this model. However, there are some exceptions.

Headings that do not influence the section depth.
A few licenses contain no-effect headings, text with the appearance and feel of headings but that does not appear to start a new section based on the section numbering in the license.

For example, the Artistic 2.0 license has a sequence of numbered subsections with no-effect headings interspersed, but through which the numbering sequence of the subsections continues unaffected. An example is Permissions for Redistribution of the Standard Version.

In such cases, the no-effect heading is modelled as the last paragraph of the preceding subsection, but formatted as a heading at its supposed level, except in a dark gray font.

Apparent changes in section depth without a heading
In a few licenses, the section depth (as indicated by section numbering in the license) changes without a heading.

For example, the Artistic 2.0 license (again), after two top-level section headings, begins numbering sections or subsections starting with (1). The meaning of the apparent heading that precedes this only applies to the first subsection (1), not to the later ones numbered (2) and so forth.

In this case, a ghost heading is placed where the new group of subsections begins, with a descriptive phrase in light gray and enclosed in square brackets. The words in ghost headings are not counted in the numbering.

At this writing, the example in the Artistic 2.0 license is the only ghost heading that has been inserted.

Mapping §¶s markup to a document

Sps mapped to document

Figure 2. §¶s markup mapped
to a document

§1¶1ṣ1 Figure 2 illustrates how §¶s markup is mapped to a document.

§1¶2ṣ1 The document title is not numbered.

§1¶3ṣ1 Paragraphs not in a section are numbered in sequence and have no section number (like the initial paragraph of this document). §1¶3ṣ2 Top-level paragraphs in a section at whatever level are numbered in sequence within that section, as are the paragraphs in this section. §1¶3ṣ2 A subsection at whatever level restarts the paragraph numbering within that subsection. §1¶4ṣ3 Within each paragraph, sentences are numbered in sequence (as are the sentences of this paragraph); ṣ3.1 clauses after the initial one of a sentence are numbered in sequence beginning with 1.

§1¶4ṣ1 Each heading begins a new section at some level: ṣ1.1 a top-level heading begins a top-level section such as §1, a second-level heading a subsection such as §1.1, and so forth. §1¶4ṣ2 Within each section, the paragraphs are numbered (1-origin), and within each paragraph the sentences are numbered (also 1-origin). §1¶4ṣ3 A dot, bang, or hook (.!?) is intepreted as marking the end of a sentence. §1¶4ṣ4 Within each sentence, a colon or semicolon (:;) is interpreted as marking the end of each clause (for lack of a more widely-accepted term): ṣ4.1 the second and later clauses of each sentence are numbered beginning with 1 for the second clause, as the marker illustrates.

§1¶5ṣ1 If the text contains no headings, or in paragraphs before the first section heading, the markers and ids begin with the paragraph number (for example ¶4ṣ1 p4 for the fourth paragraph of a document without section headings).

§1¶6ṣ1Summary of §¶s markup structure for each license

Punctuation characters

§1.1¶1ṣ1 In some cases, the characters that mark the ends of sentences and clauses appear for other purposes. §1.1¶1ṣ2 A common example is the abbreviation U.S., which contains two dots but is not two sentences. §1.1¶1ṣ3 I have identified these and marked the license source up accordingly so that the dots etc. are present in the text but do not affect the §¶sw numbering.

Numbering ranges

The licenses display section and list numbering with arabic and Roman numerals and letters, and the §¶s numbering follows their format, both in markers and HTML ids. For example, a section whose heading is numbered 1.a.i will have marker §1.a.i and HTML id S1.a.i; its first paragraph will have marker §1.a.i¶1 and HTML id S1.a.ip1, and so forth. Each use of non-arabic numbering was individually set by me.

In some cases, section numbering or list item numbering begins at 0 in the license text, in which case the §¶s numbering matches it.


Where the license contains a list, the appropriate §¶s numbering is not always obvious. The following rules, chosen with the goal of producing §¶s numbering that is both consistent and minimally arbitrary, were followed in manually determining the numbering for each list.

In all cases (such as AGPL §1¶4) where the license contains an inline enumerated list of items (often a lengthy list) within a single paragraph, the license is presented here with the inline list formatted with each item set out separately. Each list item is numbered as a separate clause (or subclause if nested). Inline lists are presented with a faint identifying background.

Terms and headings

Each license is presented with a list of links to its defined terms and section headings (if any), floating on the right margin. Note that some licenses, for example BSD, define no terms and are not divided into sections. Others define so many terms and have so many sections (AGPLv3, GPLv3) that you must choose which you wish to see at any one time.

Editorial notes and show/hide

I have added editorial notes where these seemed helpful. The notes are of course not part of the license text.

Each license has a note giving its source.

By default the notes are shown; hide (and show them again) by clicking the Hide/show notes box at the top of each license page.

There is an analogous Hide/show §¶s box at the top of each license page if you wish to hide (or re-show) the §¶s markers.

Closely-related licenses

Careful textual analysis has shown that several pairs of licenses are nearly identical:

or identical in large part:

or share substantial amounts of text:

The texts are marked up to indicate where they are identical and where they are different. Showing/hiding the editorial notes also shows/hides this markup.

Organizations and authors associated with each license

License Organization or Author Date (where known)
AFL Lawrence Rosen 2002 Nov (1.2)
By 2004 June (2.0)
2005 (3.0)
AGPL Free Software Foundation 2007 (v3)
Apache Apache Foundation 2004 Jan. (2.0)
APL University of Victoria By 2004 Apr (1.0)
Artistic Perl Foundation 2006 (2.0)
BSD University of California, Berkeley 1988 (4.3 Tahoe) 1989 (4-clause)
1998 or 1999 Jul 22 (template)
CC-BY-SA Creative Commons
CDDL Sun Microsystems 2004 Dec 17 (1.0)
CPAL Socialtext, Inc. 2007 June 25 (1.0)
CPL IBM 2001 May (0.5)
2001 June (1.0)
CPOL The Code Project c.2008 (1.02)
CTL Corel 2007 Feb.
ECL A group of universities c. 2007 Mar. (2.0)
EPL Eclipse Foundation 2004 Mar. (1.0)
Google Apps Google
GFDL Free Software Foundation 2008 Nov. (1.3)
GPL Free Software Foundation 1991 Jun. (v2)
2007 Jun. (v3)
IPA Fonts International Phonetic Association ?2005 Sep. 03 (1.0)
LGPL Free Software Foundation 1999 Feb. (v2.1)
2007 June 29 (v3)
MIT Massachusetts Institute of Technology 1986
MPL Mozilla Foundation 1998 Mar. (1.0)
1999 (1.1)
Ms-PL Microsoft 2007 Oct 12
Ms-RL Microsoft 2007 Oct 12
NASA National Aeronautics and Space Administration 2004 Mar. 23 (1.3)
OFL SIL International
(Summer Inst. of Linguistics)
2007 Feb. 26 (1.1)
OSL Lawrence Rosen Nov 2002 (1.1)
By June 2004 (2.0)
2005 (3.0)
PHP PHP Group 2006 (3.0)
QPL Trolltech 1999 (1.0)
Ruby Yukihiro Matsumoto
SCSL Sun Microsystems 2007 Jan. 17 (2.8)
zlib/libpng PNG Group 2004 Oct. 3 (1.2.2)

License selection criteria

The selection of licenses covers important and commonly used OSS licenses, plus a selection of proprietary, documentation, and other licenses. Several criteria were used:

The licenses discussed by Rosen: BSD, MIT, Apache [1.1], Artistic [1.0], GPLv2, LGPLv2.1, MPL 1.1, CPL 1.0, and his own licenses AFL [2.0] and OSL [2.0]. Where a license has been superseded by a newer version (indicated by [ ]), the newer version appears here.
The licenses discussed by St. Laurent:  MIT, BSD, Apache [1.1], Apache 2.0, AFL [2.0], GPLv2, LGPLv2.1, MPL 1.1, QPL (superseded by GPL), Artistic, CC-BY-SA[1.0], the author's Classic Proprietary License (here we use CTL as an example proprietary license), SCSL, and the MSSI licenses (represented here by Ms-PL). Where a license has been superseded by a newer version, the newer version appears here.
OSI lists
All the licenses listed by the Open Source Initiative under the category License[s] that are popular and widely used or with strong communities over the span of this research project: Apache 2.0, BSD, GPLv2, GPLv3, LGPLv2.1, LGPLv3, MIT, MPL 1.1, CDDL 1.0, and EPL 1.0.

All the licenses listed by the Open Source Initiative under the category Other/Miscellaneous licenses over the span of this research project: APL, Artistic 2.0, OSL 3.0, QPL 1.0, and zlib/libpng.

All of the licenses listed under the category Special purpose licenses: ECL, IPA Font, NASA 1.3, and OFL 1.1.

Black Duck list
All the licenses that have appeared on Black Duck Software's list of the twenty most commonly used OSS licenses over the span of this research project: GPLv2, LGPLv2.1, Artistic, BSD, GPLv3, MIT, Apache 2.0, CPOL 1.02, Ms-PL, MPL 1.1, CPL 1.0, EPL 1.0, LGPLv3, zlib/libpng, AFL 3.0, CDDL 1.0, OSL 3.0, MPL 1.0, PHP 3.0, Ruby, and Ms-RL.
Other significant licenses
AGPLv3 is included because of its distinctive provisions for software services.

The CC0 Waiver is included as an example of a public-domain dedication.

The obsolete BSD 4-clause license is included because it is often referred to even if now rarely used.

The Google Apps Agreement is included as an example of an agreement for the use of software services as opposed to the software itself.

GFDL 1.3 is included as an example of an OSS documentation license.

The UDK License is included as an example of a license with many third-party licenses, and because of its unusual licensing terms.

License texts

License texts are the approved texts from the Open Source Initiative web site, or (for non-OSI-approved licenses) the most authoritative available text. Each license page has a link to its original text.

Each license text is an accurate copy verified as thoroughly as possible, except for the small number of cases (identified by editorial notes) in which I found strong reason to believe there had been a typographical or formatting error. In those cases, text in this web directory proposes a reasonable correction (for research and educational purposes only). The verification is done automatically using software tools. From time to time as I examine the licenses in new ways and as I improve the verification software, I find new problems and correct them, so the license texts presented here are not completely static. Please contact me if you find any error in the licenses.

The licenses presented in this web directory are not the work of this researcher, and their use here is a fair use for educational purposes without commercial gain.

The annotations added to the licenses by Thomas A. Alspaugh are published under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.


Lawrence Rosen. Open Source Licensing: Software Freedom and Intellectual Property Law. Prentice Hall, 2005.
Andrew M. St. Laurent. Understanding Open Source and Free Software Licensing. O’Reilly Media, Inc., 2004.

flip bgunflip 

  1. AFL 3.0
  2. AGPLv3
  3. Apache 1.0
  4. Apache 1.1
  5. Apache 2.0
  6. APL 1.0
  7. Artistic 2.0
  8. AWS
  9. BSD
  10. BSD 4-clause
  11. BSD 4.3 "Tahoe"
  12. CC-BY-SA1.3
  13. CC0 1.0
  14. CDDL 1.0
  15. Chromium
  16. CPAL 1.0
  17. CPL 1.0
  18. CPOL
  19. CTL
  20. ECL 2.0
  21. Eclipse 1.0
  22. GFDLv1.3
  23. Google Apps ToS
  24. GPLv2
  25. GPLv3
  26. IPA Font 1.0
  27. LGPLv2.1
  28. LGPLv3
  29. libjpeg 8c
  30. MIT
  31. MPL 1.0
  32. MPL 1.1
  33. Ms-PL
  34. Ms-RL
  35. NASA 1.3
  36. OFL 1.1
  37. OSL 3.0
  38. PDDL 1.0
  39. PHP 3.0
  40. QPL 1.0
  41. Ruby
  42. SCSL 2.8
  43. UDK 2010-03
  44. UDK 2011-02
  45. Unity 3.x
  46. zlib/libpng